The Colosseum or Coliseum, originally the Flavian Amphitheatre.., is a giant amphitheatre in the centre of the city of Rome, Italy. Originally capable of seating around 50,000 spectators, it was used for gladiatorial contests and public spectacles. It was built on a site just east of the Roman Forum, with construction starting between 70 and 72 AD under the emperor Vespasian

http://en.wikipedia.org/wiki/Colosseum