Destined to host gladiator fights "munera" and hunting spectacles "venationes", and built in the valley contained by the Palatine, Esquiline and Caelian hills - on the spot where the artificial lake, Nero's Domus Aurea lay - the Flavian amphitheatre, so called in honour of the dynasty of the emperor Vespasian, who in 72 AD began its construction is known throughout the world as the Colosseum. In the Middle Ages, in fact, the massive building got this name because of the colossal bronze statues of Nero, more than 30 metres tall, located in the immediate vicinity. Inaugurated in 80 AD by the emperor Titus with a series of grandiose spectacles, lasting, it was said, for 100 days on end, and later completed by Domitian, the most celebrated monument in Rome was largely reconstructed by the emperor Severus Alexander; damaged by fire and earthquake, and used as a fortress in the Middle Ages, its marble and stone was used as recycled material for the building of new monuments and palazzos until the eighteenth century, when Pope Benedict XIV banned its sacking. A masterpiece of symmetry and elegance - given the exceptional nature of the materials used (travertine, iron cramps, marble, tuff stone, bricks and concrete) and the clever building technique - and symbol of the Eternal City, the Colosseum, with its elliptical plan (the large axis 188 m., the short one 156 m., a circumference of 527 m. and a height of 57 m.), is divided into four floors thanks to the superimposition of travertine marble arches, framed by Doric, Ionic and Corinthian half-columns, and crowned by a brickwork attic spanned by Corinthian pilasters; precisely in the attic was a huge "velarium" (a sort of large curtain) which, fixed to a whole series of poles, was manoeuvred by a team of sailors, it protected spectators from the rain or the sun. The large marble cavea, supported by internal corridors covered with barrel and cross vaulting, was destined to hold more than 50,000 spectators, and was divided horizontally, into three orders of seats, while vertically it was broken by flights of entry steps to the terraces, made of tuff stone and wood, the last of these, surmounted by a terrace used for standing only, was provided for the poorer members of the population. Finally, under the arena, is a real maze, with a long sequence of tunnels and rooms, used to hold the wild beasts and the gladiators.