Viking Age Ring Fortresses

Viking Age Ring Fortresses
Photo by Walter.

The Viking-Age Ring Fortresses are the remains of five monumental defense works that represent the stage of centralization of power in the kingdom of Denmark under King Harald.

The fortresses of Aggersborg, Fyrkat, Nonnebakken, Trelleborg and Borgring were constructed at strategic positions near important sea and land routes. The large infrastructure projects were executed within a short period in a precise and similar manner. The forts were only used for a few decades.

Community Perspective: Astraftis has provided the ultimate review for this site, covering all locations in detail. Other reviewers are less enthusiastic about these ring fortresses, of which Trelleborg is the easiest one to access.

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Frederik Dawson

Netherlands - 10-Nov-23 -

Viking Age Ring Fortresses by Frederik Dawson

I visited two of five inscribed Viking Ring Fortresses, the unknown Borgring and the famous Trelleborg on my short trip to Denmark. On the way from Copenhagen to Stevn Klint, just outside the city of Koge, I made a brief stop to see Borgring which was just next to the highway exit. After parked my car on the empty carpark, I found out that I was the only soul, no staff, no entry restriction, so I just entered to see something equally empty! Borgring was like a big playground for kids with big circle ring sandbox. There was nothing to see, no hill, no turf, only some metal or wooden frames and columns doting the whole place. My thought at that moment was “Is this a joke?” before walked back to my car.

Few days later when I drove back from Odense, I made a detour to Trelleborg. At first, I want to skip it after seeing Borgring, but after searching some photo in internet, at least Trelleborg should be more interesting. When I reached Trelleborg, the museum was closed on that day, but thanked to one comment in google review, the fortress could be visited every day via small passage next to museum building. The first thing I saw was the long wooden house, I assumed that this building should be a reconstruction of Viking houses that once located inside and surround the fortress. The boat shaped building and roof line were really interesting. Then I walked to see the fortress ring, along the way there were stones to mark the trace of many Viking houses. The earth mound fortress structure was still in good shape, so I climbed to the top to see the view. Honestly there was nothing much to see, apart from earthen ring fortress. Anyway, Trelleborg was far better than Borgring.

Too bad that all the Viking sites I saw in Scandinavia and Germany were all disappointing in some way. Anyway, the outstanding universal value was truly understandable even from the short visit in Trelleborg. The back stories of all these sites were interesting and promising but the visiting experience was totally different.

Caspar Dechmann

Switzerland - 18-Sep-23 -

There may have been a time when viking sites were underrepresented on the world heritage list but by now I think they are already overrepresented. Firstly the viking period is a rather limited era and has already 6 sites or more on the list. I haven't visited all of them but I have visited Jelling and Hedeby (and St. Kilda but there the Viking connections is not central). While I found both visits worthwhile and interesting, in both there is very little to see and they need a lot of explanation and imagination and I am not so sure at all that they really need to be on the list.

The other important viking places are Birka where seems vey little original to see but a few tumuli, and also the sites on Greenland and L'Anse aux meadows are more interesting about the early exploration of the western hemisphere than about their scant remains. 

So there seems no need to add another site that doesn't add much and is possibly even less interesting. When I travelled around Denmark I felt that visiting Jelling should be suffice for viking sites since it is the most important viking site and already very modest as a WHS. But on the way from Kopenhagen and the eastern island the Jutland I travelled through the nice city of Odense where I stayed for one night to explore the old town and the Andersen connection (I found the new museum/park about him less interesting though). Of course I made the small detour to Nonnebacken. But there is really nothing to see but a small hill so I do not understand at all why this would be included in this already very weak nomination. Perhaps they think they may make some archeological discoveries in the future similar to the arguments they used for the nomination of the similarly weak Roman Limes sites. Sometimes you get the impression they try to turn the plainness of a site in an argument for its future archeological potential. 

Nonnebacken is probably the weakest of the five inscribed sites but when you look at the other sites then you finde nothing more but a round wall. If there is anything else visible it is reconstructed. Is that really so important? After all these sites are not even so old: They are only about one thousand years old. Shouldn't there rather be an inscription of bronze age and iron age hill forts? Especially the UK has hundreds of them, all of them are much older than the viking fortresses. Many of them have also mainly earth walls left but they are much bigger and impressive. Among them Maiden Castle, Old Oswestry or British Camp. But there are also hill forts that have a surprising amount of walls and house foundations left: on my last trip to the UK I found a hike to Tre'r Ceiri Hillfort extremely impressive: the walls there are massive: several meters high and think and there are dozens of foundations of roundhouses left. A selections of these hill forts would be a much more interesting addition in my opinion. In Germany the Heuneburg is another early Celtic castle of huge importance. 

I you visit the wonderful National Museum in Copenhagen you find not only a great collection of viking finds that give a good impression of their artistic skills but also stunning finds of much earlier bronze age culture that is hardly known: among them the wonderful Trundholm sun chariot from around 1400 B.C., the strange Veksø helmets, around 900 B.C. or the collection of lures, a fascinating bronze age instrument. More great finds from that period are shown in the wonderful Moesgard museum south of Aarhus: objects of great skill and symbolic power. This culture is at least as interesting as the vikings and not represented on the list. 

If there really should be an addition with another viking site I think it should be the two viking settlements on the Orkneys and the Shetlands where you find the only examples of the complete foundations of a viking settlement anywhere (except perhaps in Greenland) because there they had to build there houses in stone for the lack of wood: the settlement on orkney is on the wonderful Brough of Birsay which offers also older settlements and a splendid hike and the settlement in the Shetlands is part of the Jarlshof which has been on the tentative list for a long time and should have been inscribed long ago.


Els Slots

The Netherlands - 05-Aug-23 -

Viking Age Ring Fortresses by Els Slots

We know the Vikings mostly for their formidable sailing and discovery of new worlds, but these five fortresses show them as nation builders and Christianizers of the Danes. I choose Trelleborg for my visit and will describe getting there on public transport and the overall visitor experience as I found it in August 2023. Regarding the question of whether this is WH material, I did some desk research as well.

The Visit

Trelleborg can be easily done as a day trip from Copenhagen Airport. There are hourly direct trains to Slagelse (1h15) and additional connections when changing at Copenhagen Central Station. The train also makes a stop in Roskilde, so you could take in another WHS along the way. Instructions for getting to the site by bus from Slagelse station are complex and the rides are not too frequent (and not exist at all during school holidays). So you have to take a taxi to cover the final 6 km, or walk. The latter is doable (I walked both ways), but not very enjoyable as you mostly walk on the shoulder of a B-road with frequent traffic.

I arrived around 10.40 and found a fair number of cars already in the sizeable parking lot. It seems to be a popular destination for families on holiday, and there were foreign visitors from the Netherlands, Belgium and Italy. The summer entrance fee is 100 DKR, which converts to a fairly high 13,50 EUR. The income seems to mostly go to activities geared towards children, such as bread-making workshops.

I tried to approach it as an archeological site but found little of interest and you would be hard-pressed to spend more than half an hour here. The use of a moat probably was the most surprising element. All features above ground except for the wall and moat are reconstructions or ‘educative tools’ of a later date – for example, hundreds of concrete blocks were added to recreate the outlines of the longhouses that stood within the walled area. It makes for better pictures but it is as fake as the infamous recreated Roman ruins in Xanten.

When it becomes a WHS, I find it should upgrade its facilities to also accommodate the ‘serious’ visitors. The experience could be much improved by offering something like a high observation tower, as the fort’s peculiar shape is best seen from the sky. More information panels should be provided, to explain the moat, the graves, etc. Regarding the lack of public transport access, I’d suggest offering rental bikes (those that you can unlock via an app or a coin) from Slagelse station. There has been talk of a new visitor center (it’s also mentioned in the nomination file) but I have no idea where it would be located and if they started its construction already.

The Evaluation

As with Kuldiga, I did my own ‘desk review’ before the ICOMOS evaluation was published. The full nomination dossier was not available yet, but the extensive Management Plan was and it included an extensive introduction to the property. It left me with doubts about the site’s OUV, especially whether it is different enough from the Jelling and the Danevirke WHS – same period, same region, same high-level purpose. The forts were only used for 10-15 years, their ‘pizza design’ did not influence future building concepts and the idea behind them only transcended boundaries when Harald Bluetooth’s kingdom was later split into Denmark, a tiny bit of northern Germany and southernmost Sweden.  

ICOMOS eventually went for Inscription advice without any reservations. Even the OUV was not challenged, although they had to make use of the ‘purple wooden fence covered in polka-dots’-theory (by which I mean that if you put enough elements into a comparison, in the end, everything will be unique; in this case, the others are not ring fortresses: Duh! And are we comparing the physical objects or their meaning?). However, the ICOMOS summary of the site I find more convincing than the one in the nomination and I wonder whether they twisted it so the outcome would be more favourable? The OUV statements for both inscription criteria are also totally different from the ones in the nomination dossier.

Read more from Els Slots here.


Italy - 05-Jan-22 -

Viking Age Ring Fortresses by Astraftis

Viking ring fortresses (ringborge) might have been the eventual factor that prompted my all-Denmark trip by rental car in August 2021 (besides massive listening to "Viking neo-folk ambient music" in the previous months as a power-background while working...). Their simple, geometric shapes emanate some mystery, and, somewhat paradoxically, they are at the same time unobtrusive landmarks and witnesses of a golden Viking age of expansion and consolidation.


As of now, there are five registered ringborge in Denmark, and they are all part of this upcoming (2022) nomination. They are neatly laid out as a string that binds together the whole country from the islands to the continent: Borgring on the eastern coast of Sjælland, Trelleborg on the Storebælt, Nonnebakken in Odense on Fyn, Fyrkat at the end of the Mariager fjord in Northern Jutland, and Aggersborg overlooking the Limfjord from the island of Vendsyssel-Thy (the northernmost part of Jutland - yes, it's an island!). There might be some connection also to the Swedish Trelleborg, which would then be a natural continuation of this string towards the east, on the other side of the Øresund, but as far as I have understood still nothing has come out in that sense. Such an arrangement is not haphazard, of course, but, then as nowadays, considering also Jelling (which fits between Nonnebakken and Fyrkat), it follows the geographical and political backbone of Denmark: remarkably, all ring fortresses lie in the vicinities of the major motorway routes (E20/E45) traversing the country, with the only Aggersborg being a medium detour. So they are quite easy and natural places to visit while exploring Denmark, or also going from Germany or Sweden towards Norway, or viceversa. In fact, they all still lie at strategic keypoints, even if modern settlements have shifted a bit: Borgring, just before the Øresund near Køge and at the same distance from Ringsted and Roskilde, when Copenhagen was still an insignificant village, if it existed at all; Trelleborg, at the Great Belt Bridge (Storebæltsbro) at Korsør; Nonnebakken in the big city of Odense in the middle of Fyn; Fyrkat on the way between Aarhus and Aalborg near the town of Hobro; Aggersborg on the former internal passage between North Sea and Baltic Sea, at a crossing of the Limfjord (Aggersundbro). This makes all logistics even easier than it already is in Denmark. The only thing to pay attention to is that (apart from Nonnebakken) they all lie at the end of more or less cul-de-sac roads on the countryside, and they are not all well signposted from every direction, especially the lesser ones, so be prepared to turn at the right point and enjoy a small ride on country roads. But it might just be me always complicating things when driving during travels (no GPS, no highways if possible).

I'll now try to give an overview of all ringborge, and then give some resuming conclusions. I will start from the one... that I did not visit. What a blunder!

The mysterious Borgring

As keen as I was on visiting the ring fortresses, of course I forgot one: Borgring. This angered me a lot, as I passed right in that area driving from my overnight stay in the middle of nowhere towards Stevns klint; but I was already far away and out of Sjælland as I realised it, and so it will need to wait for the next time. For this blackout I can just blame my excited anticipation over the contemplation of Cretacic disasters.

Fortunately in some sense, Borgring is also the least excavated and known of the lot (and therefore "mysterious"), as it was discovered only in 2014 (and given a frankly unimaginative name: the "fortress ring"). This is actually one of the reasons why I skipped it: it is not yet considered in all descriptions of Viking ring fortresses, many of which stick to the magic number of four, as it was the case in some explaining panels in Trelleborg, the first I visited... and so it just passed under my radar. Overall, it is surely the least advertised of all ring fortresses. So, WHS-seeker, beware: learn from my errors and you, at least, remember the existence of Borgring!

Facilities/To and fro and around

From the information that can be gathered, the site has visiting facilities in the form of a parking (on secondary road 150), a small exhibition, a visiting path, panels, and a viewing platform (with small entrance fee), and of course toilets and beverages in pure hygge style, but probably not yet a shop; its extension can be appreciated by means of metal poles (similarly as in Jelling) and signs on the ground that help visualise it, even if the third dimension is still lacking. All in all, it should be a pleasant, short visit at a crossroad between two WHSs (Roskilde and Stevns klint), Copenhagen, and routes to the south (e.g. Møns klint) or east (Odense and Jutland). I highly doubt there are useful public means connections to this site. Maybe there are buses to Lellinge, but it is really close (4/5kms) to Køge for a taxi... or even a walk. At the moment Borgring should be open only in summer (Jun-Aug), with standard times 10-16, but in typical Danish style the site should be freely roamable anytime. A more expansive visitor centre is already planned.


The powerful Trelleborg

Trelleborg is the hub of Viking ring fortresses. It is the most renown and organised one, as it was the first to be discovered, in 1933. It happened all serendipitiously, as the local motorcycle club wanted to make a track out of the natural oval slope of the terrain, but the precautionary custom archaeological investigation lead to the discovery of an important Viking site of the first Danish kingdom, united under the rule of Harald Bluetooth.

Despite not being the largest ringborg (the record belongs to Aggersborg), it is today the most imposing one, as it can be fully appreciated through its (partly reconstructed) tall earth and stone ramparts with their four access gates, the moat crossed by small wooden bridges, a picturesque position at the confluence of two creeks (å in Danish) in the midst of a verdant countryside with grazing cows, and big Viking festivals in summer. The small museum has a beautiful scale model, some interesting finds like an extremely rare complete, war-battered wooden Viking shield, and all possible information you might want about ring fortresses and Trelleborg in particular. In high season, there are included guided tours in the afternoon (I took the one at 13h) that take you also inside the reconstructed longhouse (which is usually accessible anyway). Tours are a nice introduction to the site and I can recommend them, even if they are not indispensable (and I personally find 13h a rather bad time point). This longhouse replica was built in 1942, and by now it is itself a charming historical artifact: it needs its own restorations and it is no more thought to be accurate, as advances have been made in the understanding of Viking building techniques. A more up-to-date longhouse can instead be found at Fyrkat. Such longhouses were geometrically placed in four identical four-house groups inside the ramparts, and some outside, but of course nothing visible remains, and only series of concrete discs along the paths convey an impression of their presence.

Besides the overall composition and atmosphere, what really sets Trelleborg apart from other ring fortresses is that it is the only one with an outer bailey and a cemetery, and the only one where we know some action happened, a violent attack of unspecified nature and purpose. Also, many burials belong to foreign persons coming from the wider Baltic region, suggesting the presence of some kind of servitude, which might have lended the name to the site (*trell ~ thrall, i.e. slave).


So, even in its apparent unsophisticatedness, this is a very complex site that can be greatly enjoyed, and overall I would say it is rightly the go-to site of this (T)WHS, if one has to choose only one. Here you will find a very complete shop with the standard assortment of Viking souvenirs, books and stuff, parking is absolutely not a problem and free (!), but unfortunately at the time of my visit there was no cafeteria, so I had to content myself of an ice cream and a hot chocolate (because this is the minimum to be expected: hygge!). Usually the site itself has no fee and one can roam freely, be it not for the Viking festivals in July/August (see section), when a hefty, and to me not really justified (at least in the particular period I was there, since no real Viking market nor activity was going on for casual visitors), entrance of 120DKK (~16€) is levied!!! Opening hours (for the museum) are standard 10-16/17 in the good season (april-october).

The way to Trelleborg is not so obvious, but it can be reached either from road 277, or road 22 from Slagelse, e.g. exiting from highway E20.


All of Denmark seems to have been in the midst of a museum-building frenzy for the last decade, and Trelleborg will be no exception: the project New Trelleborg has finally started at the end of last year (september 2021, after my visit), and the completion of the works is foreseen for the end of 2022 (look here and here). Den genskabte borg will consist of the reconstruction of a circle section of the original fortress at the side of the current visitor centre, with lots of viking reenactments and activities. The museum will also be expanded and improved a bit, but probably not so radically as in a first project I found online. It will be interesting to see the final results, and a good reason to return!

-To and fro and around

For my visit, I found Korsør a very appealing base for the night: a nice, charming town on the sea, with its old castle and port, and where you can "visit" the Great Belt Bridge, and even touch it (go here)! Otherwise, Slagelse is bigger, and probably nice too. More towards the north there's Kalundborg, which can boast a remarkable historic centre with a quite unique church and some of the oldest houses of the region. Or you can just make Trelleborg a stop on your way between Odense (other ring fortress!) and Copenhagen, or Stevns klint... or anywhere else! But chances are that, if you drive through Denmark, you will pass very near it. My only doubt is how reachable Trelleborg is by public transportation, but in all cases a taxi from Slagelse (7km) might be viable at a still human price (and from the site, hitchhiking should be easy).


The vanished Nonnebakken

To put it clearly: there isn't anything left to see at Nonnebakken ("nuns' hill"), once the smallest of the five ring fortresses. Nowadays it is just part of an elegant neighbourhood of Odense, immediately outside of the centre, on the other side of the creek (aptly called Odense å). So I hope nobody in their right mind would come here only to "perceive" Nonnebakken (right??), but if you pass through Odense, absolutely come make a stroll: it is a nice place, and in fact a good one to start a visit of the whole city. You can find (free!) parking more easily than in the centre proper, and the verdant walk across the bridge and to the fanciful eventyrhaven, "the fable garden", before reaching St. Knud's church is a nice introduction to Odense and its Hans-Christian-Andersen mood. Anyway, in a perverse state of mind, probably induced by one pile dwelling too many, I found moderate excitement in trying to evoke how this ring fortress could have been like, at the times when it represented the long arm of nascent royal power near this small island settlement known for a sanctuary (vi) to Odin (Odins vi > Odense). Now things have reversed, the settlement grew on the other side of the river and the fortress is long forgotten. And there are indeed small traces still to be seen under the superimposed modern city: first of all, the creek itself (larger in the days) which connects with the sea, as by all other rinborge; then, the slightly circular slope of the terrain, rising moving away from the creek, with the Odd Fellow building at the top. The playing ground in the park is where Vikings took their boat ashore. You can try to grasp this by walking the loop Nonnebakken-Hunderupvej-Allégade-Absalonsgade; in particular (if I understood well), if from Absalonsgade you look into the schoolyard, you are looking at the other side of the ramparts!


The street shield will tell you that you have arrived. If you are by car, I wish you will find a free parking: they do exist. There's an explanatory panel, and I am not sure if the spinning-top-like monument commemorates the fortress. You'll find some more information and a handful of finds at the city museum Møntergården, where it is told there are plans to valorise the site and give it more visual presence. Excavations have always been difficult because of the modern bustling location, so little is known, but it seems that "Nonnebakken" had itself replaced a previous fortification.

-To and fro and around

Odense is Hans Christian Andersen's realm. A new, enormous, lavish, top-architectural (Kengo Kuma) and ultra-interactive museum has most recently opened (I could only visit a "preparatory version"), replacing old H.C.A.'s house. Odense is surely worth a visit and I am sure it will be appreciated by children. As for WHSs, let's say that it sits between Jelling on the continent and Roskilde/Stevns klint (and soon Trelleborg, I feel) on Sjælland!


The lively Fyrkat

Fyrkat (probably ultimately meaning "four cats", from the name of a local mill) is on the outskirts of Hobro, a town at the end of Mariager fjord and between Randers and Aalborg, in Northern Jutland. It is tied to the Vikingecenter Fyrkat, but the two are independent, so you can ignore the centre and go straight to the ring fortress, if you like. The most scenic path is signposted and starts opposite the parking: reach the lake and then walk along its shore, until you reach the old mill farm. As in Trelleborg, you will find an oaken longhouse, but this was built under the light of more recent research: you will notice it by the more "curved" form and the lateral supporting beams, which give it a more compact, whale-like form than the one at Trelleborg. I found it empty, with a serene atmosphere, but occasionally theatrical plays are performed here. The ramparts and moat of the rinborg have been brought back to their former shape, and now it looks like a smaller version of Trelleborg, with the addition of grazing sheep. The setting is more closed and slightly wilder than at Trelleborg: you have your creek and a marshy landscape, and a wooded hill rises on the other side. I liked it a lot, and it is much more tranquil than Trelleborg, as it is also less visited. In the area, there are also interesting panels about the region and the ancient "Ox Road", or Hærvej, the Danish highway of the times, which passed here (of course, another strategic point). There was also a cemetery, and the most fascinating find was the burial of a woman of evidently exceptional status, rebaptised "the seeress" (vølve). Her apparel and accessories can be seen at the local museum (see below).

The Viking centre is nice, but I am not sure it is worthy of the relatively pricey ticket (75DKK~10€). It is an enjoyable reconstruction of a Viking estate, precisely one excavated at Vorbasse, though walls are made out of concrete, to the detriment of a complete immersion (counterbalanced by true running chickens). Interiors are reconstructed and you'll see the live enactment of different crafts: the smith, the spinner... but it dependends on the moment, you might be unfortunate. There's also a modern room for activities. Now, as a personal anecdote, to my surprise I realised that I had already been here, 14 years before!!! But then, as incredible as it may sound, we did not visit the ring fortress (that Italy-Norway road trip is a whole story of mindless youthful travelling, that's also why I didn't remember exactly...), but we were able to try a chain mail. Maybe you're lucky! As a whole, I think children might like the place. In hindsight, I preferred the same kind of reconstruction in Haithabu/Hedeby.


The Viking centre has the standard snack choice, but no true cafeteria, so no lunch here. The shop is not so big as in Trelleborg, but it has more local, less-standard Viking-themed handicrafts beside usual stuff/books, and you also find the Fyrkat beer! Parking is either here or directly at the ringborg. As usual, the ring fortress is always visitable, but the Viking centre lives in the good season (Easter & May-September, opening hours 10-15/16/17).

Also here, there are plans (officially taking place in 2022-2025) for a modern museum, Vikingemuseet Fyrkat, to open, and it will be hosted in the old millfarm next to the ring fortress. It will also include general renovations and extended exhibitions in the area, acting as the "Viking hub" of Northern Jutland. Of course, it is all somehow related to the UNESCO nomination. Anyway, another reason to return to this site (again!)!

-To and fro and around

Fyrkat seems to lie at a dead end, so you first have to drive into Hobro and then down the Fyrkatvej. It's very doable by foot, a 30-min. walk or so from the town centre (a little bit more from the train station). There's not really much to do or see in Hobro, but I can recommend a visit to the local brewery Bies! The local museum is "very" local: this means that it opens only in the good season from 12 to 16. The ticket is the same as for the Viking centre (and there's also a special combiticket for other attractions in Northern Jutland, a kind of yearly pass), but I recommend it only if you are really passionate about it, or if you have some time to spend in the afternoon. The seeress's treasure is nice, but it's not much and moreover, I was told it will be lended for an extended period of time to some exhibition elsewhere. But maybe they referred to the planned Vikingemuseet, or anyway it will surely come back there once it's ready. Outside of Hobro, there's a scarcity of (T)WHS, but Aalborg to the north is an interesting city and a good base. Or you can just go straight northwards to a ferry to Norway, or southwards to Haithabu.

A hidden sight: go inside Hobro's library (Adelgade/Nordvestvej, the door is always open), and in a corner you can admire... a runestone! Which says: "Thore raised this stone for his friend Karl the Good, a very good guy". There's hardly anything more Scandinavian than this arrangement.


The bucolic Aggersborg

Aggersborg, on the Aggersund, is the more isolated of the five ring fortresses, but I think it is worth the trip, as all North/West Jutland. It was the biggest one (48 longhouses took place inside), but its circle today is not complete, since part of it is occupied by a farmstead. With good weather, the panorama here is the most spectacular among the ringborge: you are on a gentle slope that overlooks the Limfjord with its islets, and the view sweeps over the whole region. You are definitely on the countryside here: what you get is a big meadow, probably exactly what agger meant. The ramparts are just outlined, but you can see the curve, and a stone lies in the centre point, where once a wooden watchtower stood. In its heydays, the wooden palisades of Aggersborg must have been an imposing sight for all ships using this passage between two seas (North & Baltic, avoiding to go around Skagen), and it could act as a rally point for fleets and troups before expeditions to the north, against those unruly Norwegians.

Now, beyond the natural scenery, I find that a true gem is the colorful, free exhibition (open in summer) in the building nearby. By means of beautifully illustrated dioramas, it depicts the story of the construction of Aggersborg and of some of its people, between old gods and Christianity: it's a kind of summa of Norse/Viking history & lore of the period, that you also find in other museums, in a narrative form, with references among others to Jelling. Worthy of a detour! Moreover, search for the app Aggersborg (iOS/Android): in a very simple version of augmented reality, it will help make the ring fortress appear in front of your eyes! It's only in Danish, but it's easy to use. So, as I drove away, I was fully exhilarated.


Nothing but toilets and some benches. And free Wi-Fi at the exhibition. I doubt public transport comes here. The nearest (3km) settlement is Aggersund (~300 inhabitants), at the bridge. You either come here from the south, taking road 29 from Hobro instead of continuing towards Aalborg, or from the north, road 11 between Thisted and Aalborg. Turn for Aggersund, then there are signs for Aggersborg in the proximity of the bridge. To eat, there was an inviting, but closed cafeteria outside of Aggersund, or on the other (southern) side of the bridge, a Danish "hotdoggery" (which, I like to remind, is a hot candidate to immaterial WH).

-To and fro and around

Well, you're more or less in the middle of nowhere. The spectacular road 11 goes all the way down towards Germany, following the wild west coast; in the other direction, you have some 140km to Skagen and its tip. Sand and dunes everywhere. Also, next to the bridge on the Aggersund is a bunker, a leftover of the last war. It lies abandoned there and can be entered: it's empty, but I found it a weird, slightly creepy experience to traverse its flooded rooms. More importantly, on the other side of the fjord lie the moler landscapes, an aenigmatic Danish TWHS. You can reach them on the island of Mors with the ferry on the Feggesund, some 30km farther away, or go the other way round through Ertebølle and Hvalpsund til Fur.


Overview and Viking markets

So, in the end these are all beautiful places to visit. If I were to do a ranking it would be the following:

  • The whole story in only one place: Trelleborg, even more so with the upcoming reconstruction
  • Only wandering around: Fyrkat (until the new museum will be complete)
  • Scenery more important than history: Aggersborg, with the bonus of a nicely quaint exhibition
  • If you are passing by: Nonnebakken and Borgring
  • You like pile dwellings: Nonnebakken

All these places are periodically animated by Viking fairs, markets or summer camps (like the one Clyde encountered), so this may change the experience a lot. I've gathered the following times and hope them to be accurate (one source is the wonderful guide Vikingetiden, in Danish and English, found in all shops):

  • Trelleborg: medio juli, i.e. week 29 (e.g. July 18th-24th in 2022) - Vikingefestival
    • the whole summer vacations, weeks 26-32 (e.g. June 27th to August 14th in 2022) Vikingesommer, with lots of activities and camping
  • Fyrkat (Hobro): primo august, so I reckon e.g. August 1st-7th in 2022, but I read also in the "middle of summer"
  • Aggersborg: week 34 (e.g. August 22nd-28th in 2022)



Ring fortresses represent an exciting part of Danish/Norse/Viking history: a surprisingly brief one, but with lasting consequences. They can all be traced back to around 980, as Harald Bluetooth, successor of the legendary Gorm of Jelling who "ruled over Denmark and Norway and made them Christian", consolidated his power in the realm and tried to develop a control structure. The ring fortresses are one of the most striking examples of these efforts, and they clearly stem from a common scheme: they were all built following the same strict, geometric principles with the same proportions, even if I wouldn't delve too much into a numerological or mystical kind of interpretation as sometimes one can read about (but surely I can imagine that inhabitants would give special symbolic importance to some parts like the four entrance gates, and so on). As they had risen, so few decades later they were already gone. And unfortunately, very little, if actually nothing, remains of such structures; most of their enjoyment comes from "sovrastructures" like museums (considering also existing major ones like the national museum in Copenhagen or Moesgaard, and the future ones) and reconstructions. So I'm personally not sure about their inscription: I feel that one can see OUV here, but there's too little to grasp. However, judging from other inscriptions like the Roman limites or Danevirke/Danewerk, they should fit into the list without problems, and I am confident that they will be inscribed indeed. In my ideal world, there would be a super WHS called Rise of the Viking power (yes, Viking is not the accurate term, but it has its appeal) comprising the ring fortresses, the Danevirke & Haithabu, Jelling and why not other minor sites like the bridge at Ravning Enge, or what remains of it (also part of Harald's building spree). In this sense, I think I am 50,5% in favour of inscription. If nothing else, they're scenic sights in beautiful settings, overloaded with fascinating, and very well told, history that can be appreciated firsthand.


PHOTO: I did my best to do a collage, please be merciful. Top: panorama of Aggersborg. Big left: inside of Fyrkat. Small right top: path to Trelleborg, the longhouse in the distance. Small right bottom: you are in Nonnebakken.


Malta - 12-Aug-16 -

Viking Age Ring Fortresses by Clyde

I visited this tWHS in July 2016 on the way from Jelling to Roskilde. I was very lucky to visit when the largest Vikings festival of Scandinavia was taking place. Viking sites are not the most iconic sites on the list and usually it is quite hard to appreciate the few remains without any context. Usually I'm not to keen on visiting sites when there is a local feast or festival taking place but on this occasion I really enjoyed it. There were several tents next to the remains of the Trelleborg fortress. These were made out of animal hides and all those taking part during the 4 day festival lived in conditions which most probably were simalar to those of their ancestors. Children played with all sorts of traditional games with leather or wooden toys or simply played bare foot in the mud close to the mounds. Finding this atmosphere at about 8am in the morning instead of another empty viking site really helped to appreciate the site proper. There is a small museum with one of the most important remains - the Trelleborg viking shield - as well as a reconstructed longhouse. The latter was built in 1942 as a model of the longhouses inside the Trelleborg fortress. Although the reconstruction is not an accurate rendering it still serves its purpose of shedding some light on the exterior and interior elements of a longhouse. The Trelleborg longhouses were almost identical - 30 metres long featuring vaulted walls made of thick planks with large uprights supporting the roof and a fireplace in the middle of the building. The longhouses are likely to have been painted and decorated with fine wooden carvings. Similar to the Jelling mounds, the positions of the uprights and walls of the longhouses are now marked by concrete. Inside the circular ramparts surrounded by a sort of moat, the living quarters were laid out in four blocks, each containing four longhouses in a symmetrical defensive pattern. All of the ring fortresses were constructed around 980 AD according to the same design principles of strict geometrical architecture and a symmetrical layout. The drone photos in the museum (picture) help to easily identify this layout. I'd be surprised if such an important site in Denmark and Scandinavia were not to be inscribed on the list in the near future, at least as part of a transnational WHS.

Site Info

Full Name
Viking-Age Ring Fortresses
Unesco ID
3 4
Archaeological site - Viking

Site History

2023 Inscribed

2018 Revision

Includes former TWHS The Trelleborg Fortresses (2010-2018)

2018 Upstream Process

Request, may not have been prioritized due to Denmark being a High Income Country.

2015 Deferred

As " VIKING MONUMENTS AND SITES / The Trelleborg fortresses, Denmark"


The site has 5 locations

Viking Age Ring Fortresses: Trelleborg
Viking Age Ring Fortresses: Aggersborg
Viking Age Ring Fortresses: Fyrkat
Viking Age Ring Fortresses: Nonnebakken
Viking Age Ring Fortresses: Borgring