The Colosseum or Coliseum, also known as the Flavian Amphitheatre, is an oval amphitheatre in the centre of the city of Rome, Italy. Built of travertine limestone, tuff (volcanic rock) , and brick-faced concrete, it was the largest amphitheatre ever built at the time and held 50,000 spectators. Construction began under the emperor Vespasian in AD 72 and was completed in AD 80 under his successor and heir, Titus. Further modifications were made during the reign of Domitian (81-96). These three emperors are known as the Flavian dynasty. (wikipedia.org)