Recognize this? This is Petra, an ancient Nabatean city in the modern day Kingdom of Jordan. This building is called the "Treasury," but it may have been used as a temple by the Nabateans before the Romans came through and conquered them. Yes, that entire buliding along with dozens less extravagant than it was carved right out of the side of the mountain. If you look on the edge of the building you might be able to see lines of holes in the wall where the ancient architects may have hung scaffolding to do their work.

If you don't like that description, just continue to believe that the holy grail is in there somewhere and that Indiana Jones went there to find it! I think I'm going to stick with this story!