It may not meet all your exacting requirements, but there is a T List site which includes Seamounts with volcanic actvity which you don't mention for consideration - "The Marine Protected Areas of American Samoa"
This includes - "the Muliāva area, an active volcanic seamount is growing a cone in its crater named Nafanua. The caldera is constantly transforming, causing the rise and collapse of distinct ecological communities within the crater. Nafanua is expected to breach the sea surface within decades, creating a new island in the Samoan archipelago and representing an outstanding example of ongoing ecological processes in the evolution of marine and terrestrial habitat. "

This article from 2006 states
"Submersible exploration of the Samoan hotspot revealed a new, 300-m-tall, volcanic cone, named Nafanua, in the summit crater of Vailulu'u seamount. Nafanua grew from the 1,000-m-deep crater floor in <4 years and could reach the sea surface within decades" so it would seem to be more than 100m below the surface (at the moment!).

I don't really see the need for the eruptions to be visible "breaking through the waterline" - being terrestrially "visible" wouldn't seem to be a requirement for OUV if underwater "value" is present?! You raise the issue as to whether the List needs more "volcanism". The closer an eruption is to the surface I suppose the less different the geological processes are going to be compared with those on land? Deep Sea eruptions are going to involve much greater pressures and hence different "flows" - but you are excluding them (though apparently such deep sea volcanism consitutes the majority of the earth's volcanic activity and has its own special features such as "megaplumes"). Maybe the aspect of a volcano rising at a hotpsot from the sea floor plate is different from that on a continental part of a plate? I am not an expert! But the underwater ecological impact of even shallow volcanism is of course very different from that which is land based anyway and would, I guess, provide its own special "OUV".

How to choose between the (surprisingly large to me) number of undersea volcano candidates? Unlike Waterfalls, size etc doesn't seem relevant. Preservation and amount of scientific study would seem important, however. Also the existence of a marine-scape with variety. I wouldn't see an inscription covering simply an underwater volcano - you don't want to have to choose extra sites unnecessarily to cover the overall potential marine OUV. The US T List entry would seem to be quite good in that respect? A problem for you might be that the volcano is "soon" to breach the surface - but, from what I read, other candidates have already done so and rely on erosion and tectonic movement to maintain their current "under water" state. And the "less than 100m depth" requirement isn't going to confer longevity on an active volcanic site!!

1. 100m: I made the decision to exclude all possible sites where all parts are at least 100 m below sealevel. I am of the opinion that there should exist at least the theoretical possibility to visit every site without a submarine. Additionally I want to prevent blowing up of the list further. Not excluding these areas would have given a lot of options to do so. Discussible, but I stick to it.

2. Interestingly IUCN has no problems with missing submarine volcanoes. See their thematic study from 2009.

3. In the meantime in August Fukutoku-Okanoba gave birth to a new island. It's not clear, if it will survive, probably not like the predecessors. The best way for solving this case, if the necessity is seen by anybody, is by including this submarine volcano into nearby WHS Ogasawara Islands, although the AB denied the OUV of the islands for Earth's history and geological features in its evaluation. Maybe a possible inclusion will change this.

And is causing a few problems......
https://www.theguardian.com/world/2021/oct/30/japan-ports-swamped-by-pumice-spewed-from-undersea-volcano


No "necessity" ... and it is your list which we are merely commenting on - not "owning"! IMO - the "best way" to handle "undersea volcanoes" as a category is to let USA nominate its T List entry and see what happens. In the mean time the "gap" is of no great significance. Adding to Ogasawara is an artificial "cop out".

I am of the opinion that the OUV of Ogasawara Islands is not for Crit iX, but for Crit Viii. So I am opposing the decision of the AB and think that it makes sense to include another island supporting this redefinition. Therefore it's not an artificial "cop out". But maybe it is necessary to skip some other islands of the site when redefining.

Case No. 8: Non-hominid fossils

Explanation: WHS for Non-hominid fossils should give an overview of the development of animal und plant life in former times. Still there are huge time gaps on the list (see the timeline). Traditionally the subdivisions of the development of life follow the geologic time scale. After thinking of alternatives e.g. pre and after the five mass-extinctions (Ok, six with the on-going), important steps of life (e.g. Cambrian explosion, going onshore, appearance of flowering plants) I decided that the community and I don't have the task to introduce a revolution in palaeontology and walked back to the accepted divisions.

Task: Therefore I look for sites of an ideal type filling the gaps or replacing existing ones in the timeline from Cambrian to Quarternary for plants and animals (terrestric and marine), 1-2 for each geologic period (!), so at least 12 each, but mixed ones are also possible if existing. Paleozoic (being an era by definition) does not count. I have some in my mind of course, but I am completely open for proposals by a brain-storming of the community. Only the addition of La Brea Tar Pits in Quarternary is a set one I think.

Side-Task: What about the independent developments in Australia (Marsupials) (Australian Fossil Mammal Sites) or South America before the Great American Biotic Interchange (e.g. TWHS Pehuén co - Monte Hermoso)? Do they belong to a Dream List or are they too specific for including? What do you think?

To be honest, there are some cases I have not expected to get answers. Non-homind fossil sites have been one of them. I think a) you have to be a good expert in this field to answer the raised questions and b) although the community acceptes their importance, these sites are boring for most of us so that people are not interested in discussing them. But I wanted to make a try. Thanks.

I made up my list, but I am still unsure for Devonian and Cretaceous.
Devonian: If Miguasha WHS is declared to be set (should it?), the second one for this period could be Rhynie Chert (UK) (plants), Gogo-Formation in Windjana-Gorge NP (Australia) or Hunsrück Slate at Bundenbach (Germany) (both marine animals). Gogo-Formation tends to be more fish related, whereas Hunsrück Slate presents a more diverse marine life of the time.
Cretaceous: For the Dinosaurs of this time I have to choose between the existing WHS Dinosaur Provincial Park and a potential new serial site, I would call "Dinosaur fossil sites of Neuquen Province" (Argentina). Here the really big ones (Argentinosaurus, Titanosaurus) have been found. But is it strong enough to kick the Canadian competitor out of the list?
For everyone who asks "What about the Badlands in the Dinosaur Provincial Park?" I can give the answer: My WHS Dream List will contain Badlands NP in South Dakota for badlands and prairie ecosystem.

What do you think about the aspects for these two geologic periods?

It's a difficult topic indeed. Also not sure whether you'd need a record from every period - if there hasn't been found an excellent example, then skip the period. That's what we do with cultural sites as well.


IUCN documentation states that Stevns Klint covers it (without the dinosaur bones). Don't know if you had included Stevns Klint in your final list?
And then there are the dinosaur footprint sites (Bolivia, Spain)

elsslots
For Silurian and Ordovician it has really been a problem, because I have been looking for sites where a larger amount of relicts has been found, not just a few prints/bones. Especially for dinosaurs areas with a huge concentration of fossilised bones/trunks are the best examples for showing life in former geological times. Therefore I skipped Stevens Klint from the list (but included Chixclub impact crater for the geological event and the relly beautiful centotes). Also imo the dinosaur footprints (e.g. Cal Orcko, really considering for a long time) can't be a replacement to the remained bones, especially when having skeletons.

But thank you for answering, Els. I know, it is really a problematic case.

Am perfectly prepared to discuss. I am not sure whether I am in sympathy with the objective but, herewith, a few thoughts for you to accept or reject as you wish! In any case some extra "knowledge", understanding or insight might emerge!

IMO, Palaeontological sites (PS) are not so much "boring" as not being really suitable for WHS inscription. They must be the only WHS where all the known heritage objects have been dug up and taken away!! Does one visit them to see where the objects were removed from - which doesn't seem very productive - or to see somewhere where there may (or may not) yet be more similar (or even as yet unknown) finds - which also seems a bit "mystical"? I know that "World Heritage" isn't (or isn't supposed to be) about people "visiting" the sites - it is (or should be) primarily about preservation. Clearly any area of fossil bearing strata which records an aspect of the World's geological/natural development, and may yet yield more, is worth preserving but, for better or worse, the visibility of an inscribed WHS IS important and Fossil sites don't really provide that possibility. Other schemes such as Geoparks could adequately carry out the preservation and educative/interpretive functions.

Many existing PS are really only worth visiting for the nearby museums. I think of Monte San Giorgio - the museum in Meride is very fine, both for its contents and as an example of the work of Mario Botta - but its location "on site" isn't really essential and can be seen primarily as a "tourism attraction" feature. And Italy's "extension" for that site is undoubtedly driven by its race to try keeping up with China's WHS count!
We have visited a fair number of PS (both hominid and non-hominid) and I can't say that, beyond the museum, they have proven memorable or even worth while. Even Olduvai didn't really add much, other than a wonder that they were able to find anything there!! One minor exception was at Messel Pit where, although it wasn't a part of the normal tour, our guide kindly took us further into the pit to see examples of the strata being split and examined by a research team. Another was a Dinosaur Footprint site in Korea where there was at least something to see still in situ - and a nice (albeit "general") fossil museum. The reality was however that it was run as a theme park on Dinosaurs for kids – and IUCN has already told Korea that it doesn't think much of Footprint sites!

So, if one isn't drawing up a "dream list" of sites to "see/visit", what about a list of "dream sites" to be preserved (whether as WHS or under some other protective scheme) - what criteria should be taken into account? You suggest "Achieving an overview of the development of the World's animal and plant life". There are "overviews" .... and "overviews". Just (partially) covering the current range of nature on Earth has already taken around 250 WHS. And to try to cover its development since pre-Cambrian times across the range of ecosystems and types of life forms across the continents then existing adds another major dimension.

As an example of the problem of choosing. You debate the potential representative site(s) for the Cretaceous. This period is of course "famous" as the era of the Dinosaurs. The obvious choice would be to go for somewhere where good examples of the iconic dinosaur megafauna of the Late Cretaceous had been found. You suggest a choice between Canada's Dinosaur Provincial Park and a selection of Dinosaur sites from Nequen in Argentina (Though Mongolia might have something to say about that!). But isn't that a bit like representing the entire Holocene by a selecting a park containing the "Big 5"? We really need to cover, inter alia, birds, plants, mammals, fish, reptiles etc etc etc all of which underwent significant development across the period even if they are not as "exciting" as Dinosaurs!.

What other aspects of the Cretaceous period could be considered? One significant geological aspect was the relatively small area of land and the existence of many shallow marine areas. So why not consider sites in Colombia which has some fine fossil areas which cover the Cretaceous fauna of the proto-Caribbean? If you are into early Crocodiles and Turtles then this is the place for you!! If it is "BIG" that you want then you can visit the Museum at El Fosil which consists of a single example of a large, albeit baby (!!), Kronosaurus. The area around Villa de Leyva is excellent for marine fossils from the Cretaceous and they are nicely shown at the Palaeontological Research Centre. Are sites which yielded fossils of Dinosaurs more "dream" in your opinion than those which yielded Crocodiles/Turtles etc?

It could also be said that almost the most important evolutionary development of the Cretaceous was the emergence of small mammals which could develop post KT. Shouldn't a Cretacious fossil site have such examples? Perhaps, the best choice of site to "represent" the Cretacious should be one with a mix of faunal types from the period rather than just Dinosaurs? I understand that the Hell Creek area of Montana yields such a range of fossils.

This forum is about WHS so it would seem best at least to look at the current T Lists before bringing in other sites! I have had a quick look through the current T Lists for their hominid PS (I may have missed some as the titles are not always explanatory and I didn't check every T List site unknown to me). I found 17 or approx 1% of the total T List. The Cretaceous in general and "Dinosaurs" in particular figure frequently and "footprints" are popular! What do you think about them? Are there any gems awaiting nomination – or yet more dross? I have indicated the period from which the fossil OUV is being claimed.

Pehuén co - Monte Hermoso (Arg) - Cenozoic
https://www.worldheritagesite.org/tentative/id/5851
Flinders Ranges (Oz) - Cambrian
https://www.worldheritagesite.org/tentative/id/6524
Cal Orck'o: Footprints of time (Bol) - Upper Cret
https://www.worldheritagesite.org/tentative/id/1816
Guizhou Triassic Fossil Sites (Chi) - Triassic
https://www.worldheritagesite.org/tentative/id/6381
South of Ricaurte Province (Col) - Cretacious
https://www.worldheritagesite.org/tentative/id/5771
Tatacoa Desert (Col) - Cenozoic (Miocene & Pleistocene)
https://www.worldheritagesite.org/tentative/id/5766
Moler landscapes of the Liim Fiord (Den) - Lower Eocene/Paleocene
https://www.worldheritagesite.org/tentative/id/5474
Bosque petrificado de Puyango (Ecu) - Mesozoic
https://www.worldheritagesite.org/tentative/id/1081
The Ipolytartnóc Fossils (Hun) - Neogene
https://www.worldheritagesite.org/tentative/id/1502
Eocene Marine Biodiversity of the Alpone Valley (It) - Eocene
http://whc.unesco.org/en/tentativelists/6539
Cretaceous Dinosaur Fossil Sites in the Mongolian Gobi (Mon) - Cretaceous
https://www.worldheritagesite.org/tentative/id/5944
Paleontological Sites of Pisco and Camana Basins (Per) – Neogene/Paleogene
https://www.worldheritagesite.org/tentative/id/6418
Sites of fossilized dinosaurs throughout the Southern seacoast (Kor) - Cretaceous
https://www.worldheritagesite.org/tentative/id/1640
Sinpetru (Rom) – Late Cretaceous
https://www.worldheritagesite.org/tentative/id/559
Le Permien marin de Jebel Tebaga (Tun) - Permian
https://www.worldheritagesite.org/tentative/id/6087
Dinosaurs and Caves of Koytendag (Tkm) - Cretaceous
https://www.worldheritagesite.org/tentative/id/5434
Petrified Forest National Park (USA) – Late Triassic
https://www.worldheritagesite.org/tentative/id/5253

I have not included a T List site from Tunisia titled "Le Stratotype de la limite Crétacé-Tertiaire (limite K-T) " because, unlike the Stevns Klint inscribed site, the T list description makes no mention of fossils but concentrates on the mineral remains containing meteorite elements. Though it is not clear why there should be a difference See - https://www.worldheritagesite.org/tentative/id/6088

(PS Els. Could it be worthwhile having an exercise to assign a "Category" to each Tentative site. This would enable the 1725 to be examined more easily by type and could throw up some interesting data on the number of "me too" sites of each type and the presence of genuine value and novelty. We could start by using the same Category list as for inscribed sites?)

Yes, we can. Let me tinker a bit with the database first to allow for the data to be entered.

Solivagant
I presented the two cases to show where I am not so sure with my list. I plan to have up to three representative sites for each periode at least from Triassic on. For Cretaceous e.g. I have also choosen Santana-Formation (Brasil) for marine and terrestric animals and plants of the earlier part of this period and a modified Cretaceous Dinosaur Fossil Sites in the Mongolian Gobi (Bayanzag, Ukhaa Tolgod) because here - opposite to the title - early small mammals and birds have also been found. So I am already aware that the life of this time did not only consist of dinosaurs. The same with other periods, if possible.

Additionally to Cretaceous Dinosaur Fossil Sites in the Mongolian Gobi I have on my dream list fixed Petrified Forest National Park (USA) and Paleontological Sites of Pisco and Camana Basins (Peru). I have been thinking of Flinders Ranges (Oz), Pehuén co - Monte Hermoso (Arg) and Cal Orck'o (Bol), but decided against in the end. Eocene Marine Biodiversity of the Alpone Valley (It) has only been rejected because an extended Wadi al-Hitan (Egy) can fill the gap also.

Now it's time for the "tech freaks".

Case No. 9: Modern Observatories (20th and maybe 21st century)

Preface: Observatories for Radio Astronomy are not part of the discussion. So neither Jodrell Bank nor the now destroyed Arecibo (Top missing list 2020).

Explanantion: Atm there are two observatories from the 20th century on the list, but not because of there own value, but because being part of another WHS with a different main emphasis: Babelsberg (early 20th century) as part of Potsdam and Teide (late 20th, early 21st century) as part of Teide National Park. But I am of the opinion that they are not really world class. In Potsdam most of the instruments have been removed after 1945 for rebuilding an observatory on the Crimea destroyed by the German during WWII. It's now hosting a library. At Teide the telescopes are rather small compared to the newest ones. Due to growing air pollution it has been decided to build the last generation in other parts of Spain/the world.

But there are alternatives having a value of its own.
1. For the early 20th century there is another possible choice in Potsdam. The Large Refracting Telescope with the Einsteinturm next, a major building of expressionist architecture, where Einstein worked in the 1920th till he had to leave Germany in 1933. Another option is the famous Mount Wilson Observatory in California where major discoveries in astronomy have been made from the 1920th to the 1940th (e.g. dark matter, expansion of the universe, milky ways beyond our milky way).
2. For Teide there is the possibility to go full modern and inscribe observatories like Mauna Kea (Hawaii, USA) or Paranal / La Silla (Chile) (It's a dream list so don't talk about getting reality).

I think for Babelsberg a replacement is necessary, for Teide I am not so sure.

Questions:
1. To replace Babelsberg would you choose Large Refracting Telescope / Einsteinturm or Mount Wilson?
2. Is Teide sufficient as an example for observatories in the late 20th century? If not, would you prefer Mauna Kea or the Chilean ones?

I have come across this Web site which might be of use to anyone interested in Fossil sites around the World. It seems a useful resource on the subject. Follow the link to Fossil sites
and to
Lagerstätten
"The world's Laggerstatten (Lagerstätten or Lagerstaette) span some billion years of geological time, and comprise the most important portion of the fossil record for the understanding of evolution. The listing below of the world's major Lagerstätten begins with the oldest, the some billion year old Bitter Springs of Australia, and ends with the 20,000 year old La Brea Tar Pits near Los Angeles, California (USA). A Lagerstätte.........is a fossil site exhibiting extraordinary preservation and often faunal or floral diversity. The word Lagerstaette translates from German as Lager and Stätte; literally meaning "place of storage"; the plural form is Lagerstätten)."

This topic has kind of dropped off with the focus on categorization of TWHS, but observatories are an interesting idea. In an ideal world the Mauna Kea observatories would make a great site (I would prefer them over Teide), but management is tricky there (the telescopes are operated by numerous countries, and the lease for most of the land is set to revert to the state of Hawaii in the 2030s). Additionally, Mauna Kea is sacred to the Hawaiian people. Incidentally, any large astronomical complex with telescopes owned by many nations, such as Teide, Roque de Los Muchachos, and Mauna Kea, may have management challenges.

I would recommend Lowell Observatory in Flagstaff, Arizona, over Mount Wilson Observatory in California, though both have points in their favor. Lowell is where Pluto was identified, and it was where early research into galaxies led to the understanding that the universe is expanding. Additionally, astronomers at Lowell mapped the moon there in support of the Apollo space program. Mount Wilson, as you noted, was instrumental in the discoveries of dark matter and galaxies beyond ours; additionally, in the early 20th century, Mount Wilson housed a couple of the world's largest telescopes. I still prefer Lowell.

After a minor accident last WE (When going down a spiral staircase in a restaurant, one should look at the steps and not at the band playing) and following the interesting TWHS categorization discussion, here is the next case.

Case No. 10: Automobile plants

Explanation: Ford River Rouge Complex is mentioned (and the obvious choice at the first glance) if it comes to automobile plants. But I have the feeling that authenticity is missing strongly. Therefore I have the tendency to take Volkswagen plant at Wolfsburg instead: At least a lot of the facades/original workshops existing, industrial (urban) planning, Nazi-Architecture (imo missing in general till now). Negative: Modern soccer stadium next to it (Greetings to L-Pool).

Question: Is there enough authenticity at Ford River Rouge Complex to take it as an example of automobile plants? Yes or No.