Looking for the best Rome underground sites? Like the catacombs, the Colosseum, and the source of the Trevi Fountain? Find out how to see a whole other Rome beneath the surface.

Rome has been here nearly 3000 years. Can you imagine it all just staying the same through time? Of course it didn't. It was like a living breathing thing that grew and shrunk, and grew again. It also sank. Over millennia of flooding, earthquakes, sacking by Goths and Vandals, and other calamitous events, much of ancient Rome is now underground.