The ancient city comes to the fore at the most iconic of Rome's sights. The circular, three-tiered archaeological landmark is amazingly intact after almost 2,000 years. Up to 50,000 Romans could congregate here to watch bloody gladiatorial contests and wild-animal hunts. There are no such dramas today, but it isn't hard to imagine those of past millennia. This is particularly true when you peer down into the shafts where elevators once hoisted beasts to their fate.