This is the inside of the Colosseum. It was begun by Vespasian in 72 A.D. and completed by his son Titus in 80 A.D.

It's true name is the "Flavian amphitheatre". It got its nickname from its size and from its location next to the Colossus of Nero. According to historical accounts, they used to fill it with water and stage naval battles here!

This picture shows the corridors beneath the floor of the amphitheatre, where men and beasts were lifted up to the arena floor to pop out at unexpected moments.

While modern sensibilities abhor the bloodshed and violence that characterized the games that went on here, it's hard not to be impressed by the sheer size of this structure. Romans clearly took these games very, very seriously.

Here it is in its recreated glory: