Colosseo.

The Colosseum may be one of the most amazing things that I have ever seen.  It is hard to imagine that that stadium entertained so many thousands of people.  We saw an underground entrance possibly for slaves and/or animals.  Our tour guide also told us that the holes on the outside were for poor people to climb up and watch.  We didn't get a chance to go inside but from what we did see, it was an architectural masterpiece.