The Colosseum

In front of you rises the largest amphitheatre Rome ever built. Its official name was the Flavian Amphitheatre, after the dynasty that raised it: Vespasian began it around AD 70 on the site of the artificial lake of Nero's Domus Aurea, and his son Titus inaugurated it in AD 80 with games that, according to ancient writers, lasted a hundred days.

1A stadium for an entire city

Estimates of its capacity range from about 50,000 to more than 70,000 spectators. People came in through numbered arches and were seated by rank: senators at the bottom, women and the poorest citizens right at the top. A gigantic awning, the velarium, worked by sailors from the fleet, provided shade. Beneath the arena, a maze of corridors and lifts, the hypogeum, now exposed, made wild animals and scenery appear as if from nowhere.

2From arena to quarry

Gladiator fights died out in the 5th century. Then came earthquakes, such as the one in 1349 that brought down much of the outer ring on the south side, and centuries of plunder: its travertine went into palaces and churches. The holes that pepper the façade are not battle damage. They are the sockets of the metal clamps that once held the blocks together, prised out so the metal could be melted down.

The name Colosseo caught on in the Middle Ages and, according to the most widely accepted explanation, comes from the Colossus, a gigantic statue of Nero that stood nearby.

3What to look for

• The Roman numerals above the arches on the north side, the best preserved: they marked each spectator's entrance.
• The three orders of columns stacked one above the other: Tuscan at the bottom, Ionic in the middle, Corinthian at the top.
• The corbels on the top storey, which held the masts that supported the velarium.