I think this is a classic example of gameplay trumps realism. Personally, I don't care if it was build on Tundra in reality. In game context, it seems pretty clear to me that the wonder is intended as a tundra-Petra. As such, it should require tundra.
Maybe the relics slots are historical although I don't know any famous relics there.
I've rationalised that since there are no seasons in the game tundra in the case of this wonder is a generic snowy landscape.
Maybe some icons but i don't know if there are any particularly famous ones there.
I tend to think there are enough famous, unique buildings that you can make the effect fit the wonder and if it really isn't working pick a different wonder instead.