Was commisioned in AD 72 by Emperor Vespasian. It was completed by his son, Titus, in 80, with later improvements by Domitian.
The Colosseum is located just east of the Roman Forum and was built to a practical design, with its 80 arched entrances allowing easy access to 55,000 spectators, who were seated according to rank.
The Coliseum is huge, an ellipse 188m long and 156 wide. Originally 240 masts were attached to stone corbels on the 4th level.
Just outside the Coliseum is the Arch of Constantine (Arco di Costantino), a 25m high monument built in AD315 to mark the victory of Constantine over Maxentius at Pons Milvius.
Emperors used the Colosseum to entertain the public with free games. Those games were a symbol of prestige and power and they were a way for an emperor to increase his popularity.
Games were held for a whole day or even several days in a row.
They usually started with comical acts and displays of exotic animals and ended with fights to the death between animals and gladiators or between gladiators. These fighters were usually slaves, prisoners of war or condemned criminals.