The Colosseum :The ancient Romans were great builders

The Flavian Amphitheater

The  amphitheater was built by Emperor Vespasian, founder of the Flavian Dynasty. Started in AD 72  it was completed in AD 80, the year after Vespasian's death. It is considered an architectural and engineering wonder, and remains as a standing proof of both the grandeur and the cruelty of the Roman world. It stands as a glorious but troubling monument to Roman imperial power and cruelty

 It was built on the site of an artificial lake that was part of Nero's huge park in the center of Rome. The area also included the Golden House (Domus Aurea) and the nearby Colossus statue of Nero which  also gave the building its current name.

Nero, after the great fire at Rome in AD 64, had built a huge pleasure palace for himself (the Golden House) right in the centre of the city. In 68, faced with military uprisings, he committed suicide, and the empire was  in civil wars The  winner Vespasian (emperor 69-79) decided to support   his regime by building an amphitheatre, a  pleasure palace for the people. The Colosseum was a grand political gesture for Rome. It was the largest amphitheatre in the Roman world, capable of holding 55,000 spectators who could enter the building through no less than 80 entrances.
The elliptical building is immense, measuring 188m by 156m and reaching a height of more than 48 meter (159 ft).  

There were  over 250 amphitheatres in the Roman empire - so we can consider the amphitheatre and its associated shows  the quintessential symbols of Roman culture.

The lowest storey was preserved for prominent citizens. Below the ground were rooms with mechanical devices and cages containing wild animals. The cages could be hoisted, enabling the animals to appear in the middle of the arena.

The ancient Romans were great builders. They built things to last. The Colosseum was made of limestone, brick, concrete, and marble , as were most amphitheaters. Anyone could attend the events in the Colosseum. Admission was free.   There were four stories of windows, arches, and columns. 
 Under the emperor Titus, Vespasian son, the Colosseum was completed. Often it is confused with the Circus Maximus (which was used for the chariot races). The Colosseum was the venue for gladiatorial and animal fights, rather than races. One thinks, the arena could even be flooded for purpose-built ships to enact naval battles.