Brass sestertius of Titus, showing the Colosseum

This is the image of one of the greatest surviving buildings from ancient Rome.
Roman coins often depicted buildings and monuments in the city of Rome. The Colosseum is easily recognized because so much of it still survives to this day. Its ancient name was the Flavian Amphitheatre, after the Flavian dynasty founded by the emperor Vespasian (AD 69-79). It was planned during his reign, but dedicated and opened by his son, Titus, in AD 80, the year when this coin was made. The Colosseum is a marvel of ancient engineering. With an estimated capacity of 50,000, seats were arranged in three tiers corresponding to the bottom three of the four storeys visible on the coin. The oval-shaped structure measures 188 by 156 metres (205 by 170 yards) and is 52 metres (170 feet) high.
The arena itself had a wooden floor. Underneath it were located cages for beasts, and drains. These were to service the events that took place in the amphitheatre, including gladiatorial combat and wild beast fights. The word 'arena' comes from the Latin for sand, which covered the floor to soak up the large quantities of blood spilt during the entertainments. Sometimes the arena was filled with water for staging mock sea-battles fought between prisoners of war and condemned criminals.