If we know of only one building in ancient Rome, it is sure to be the Colosseum. The Colosseum is an amphitheatre, that is a theatre in the round, or in this case an oval.
The Colosseum was built on part of the grounds of the palace that belonged to the bad emperor, Nero. Emperor Vespasian did this to rid the city of Nero's memory. But the Colosseum is still named for the colossal 40m high golden statue of Nero that once stood near here.