I Found a Graphics Bug
I was exploring around Ramses' territory with my scout. Thebes was a coastal city, and it just so happened that he also built Stonehenge.
I was quite shocked to see several 500-ton stones floating in the middle of the ocean in perfect formation!
Might want to prevent that from happening in a future patch, although it was quite humorous to see that.
Oh yeah, and in the Civipedia, perhaps it would be a good idea to mention that the Sydney Opera House can only be built on a coastal city. I had a hell of a time figuring out why I couldn't build it in my last game.
It happened to me too with the pyramids and a few more.
This isn't a graphics glitch, its a feature they didn't think through properly.
Maybe they just built it in a fairly shallow patch. You know, float the stones in, set them on the sandy bottom...