Ok - I'll try to construct something postive and feasible for the time being. I'll start with Europe as it's the continent I know best. The same would have to be continues for the rest.
I will refer to this connection as "connected to a living ethnos" (no exceptions, Solivagant)
This still raise many problems but I'll try to adress them as they come.
Greeks - [should we relate to Ancient Greek sites as connected with the Greek ethnos? I would say yes. What about Byzantine sites? I would still say yes.]
Butrint, Gjirokastra, Troodos, Paphos, Agrigento, Aquilea, Ravenna, Syracuse, Troy, Xantos, Ephesos, all Greek sites
Catalans - [Andorrans, Belarians and Catalans (in France and Spain) regard themselves as such. Valencians usually don't. As to Spain - I'll exclude only the acknowledged national minorities: Andalusians, Catalans, Basques and Galicians)]
Andorra, Ibiza, all Catalan sites
Austrians - [I'll seperate them from Germans although this distinction is new for ethnos. Nonetheless German ethnos remains the default for sites outside these countries]
All Austrian sites apart from the railway.
Flemings - Brusselx2 (sites were constructed in a time where they were the majority), Bruges, Beguinage, Belfries (a Flemish symbol)
Waloons - Tournai
Bosniaks - Visegrad, Mostar (despite being originally Turkish)
Bulgarians - [I excluded the Thracians] Boyana, Ivanovo, Nesebar, Rila
Dalmatians - [many Istians and Dalmatians in Croatia feel ethnically distinct]
Split, Stari Grad, Trogir, Dubrovnik, Sibenik
Istrians - Porec
Czechs - [Moravian/Bohemian are not such strong ethnic identities. I ignore German influence apart from Valtice]
all sites apart from Brno, Lednice and Trebic
Danes - Roskilde, Elsinore
Estonians - Tallinn