Colosseum...

The Colosseum or Coliseum , also known as the Flavian Amphitheatre  or Colosseo , is an oval amphitheatre in the centre of the city of Rome, Italy. Built of travertine, tuff, and brick-faced concrete, it is the largest amphitheatre ever built.

The Colosseum could hold, it is estimated, between 50,000 and 80,000 spectators, having an average audience of some 65,000; it was used for gladiatorial contests and public spectacles such as mock sea battles, animal hunts, executions, re-enactments of famous battles, and dramas based on Classical mythology. The building ceased to be used for entertainment in the early medieval era. It was later reused for such purposes as housing, workshops, quarters for a religious order, a fortress, a quarry, and a Christian shrine.

Although partially ruined because of damage caused by earthquakes and stone-robbers, the Colosseum is still an iconic symbol of Imperial Rome. It is one of Rome's most popular tourist attractions and also has links to the Roman Catholic Church, as each Good Friday the Pope leads a torchlit "Way of the Cross" procession that starts in the area around the Colosseum.
https://en.wikipedia.org/wiki/Colosseum