There are also naturally occuring underwater structures that have carvings on them. That’s because somebody got around to whack away at them when the ocean level was lower. Anyone who gets stuck on the offshore “structure” in Souvrn’ Japan should take a good look at the Giants’ Causeway in Great Britain: http://www.google.com/search?q=giants+causeway&hl=en&prmd=ivnsm&tbm=isch&tbo=u&source=univ&sa=X&ei=FqKtTbeCEKjg0gGD-NWhCw&ved=0CCwQsAQ&biw=1333&bih=690
There are fossils of sea creatures contained in rock on top of the highest mountain in the world.