seancolorado
Deity
Machu Picchu and Neuschwanstein each require a mountain within 2 tiles. Petra requires desert within 1 tile. Sydney Opera House, The Colossus, and The Great Lighthouse each require coast within 1 tile.
I suppose that adding further restrictions could be fun. Which ones would you add, though? Certainly, we can't say "must be built in Greece" or "must be built in the new world" and other geographical restrictions should make sense (Machu Picchu without mountains wouldn't be very wonderful). Some wonders probably can't be restricted (i.e. The Great Firewall, Hubble Space Telescope).
I wouldn't mind seeing a tundra exclusive wonder or even a wonder that can only be built on a marsh (i can't think of what wonder that would be...maybe that's why there are none...).
I also like the idea that was just mentioned that certain wonders would not be allowed to be built in the capital