Colosseum in the city of Rome

The Colosseum is the famous tourist spot in the center of the city of Rome in Italy visited by millions of visitors annually. It is also called as Roman Coliseum, originally the Flavian Amphitheatre which is derived from Latin word Amphitheatrum Flavium. It is an elliptical amphitheatre which is the largest ever built in Roman Empire and greatest works of Roman architecture and Roman engineering.

The Colosseum a site just east of the Roman Forum, its construction started between 70 and 72 AD under the emperor Vespasian and was completed in 80 AD under Titus, with further modifications being made during Domitians reign on 81–96. The name "Amphitheatrum Flavium" derives from both Vespasians and Titus family name Flavius, from the gens Flavia. The building was remodeled further under Vespasian's younger son, the newly designated Emperor Domitian, who constructed the hypogeum, a series of underground tunnels used to house animals and slaves. He also added a gallery to the top of the Colosseum to increase its seating capacity.

The hypogeum was connected by underground tunnels to a number of points outside the Colosseum. Animals and performers were brought through the tunnel from nearby stables, with the gladiators' barracks at the Ludus Magnus to the east also being connected by tunnels. Separate tunnels were provided for the Emperor and the Vestal Virgins to permit them to enter and exit the Colosseum without needing to pass through the crowds.

The Colosseum is an entirely free-standing structure. It derives exterior and interior architecture from two Roman theatres back to back which is elliptical in plan and is 189 meters / 615 ft / 640 Roman feet long and 156 meters / 510 ft / 528 Roman feet wide, with a base area of 6 acres / 24,000 m2. The height of the outer wall is 48 meters / 157 ft / 165 Roman feet. The perimeter originally measured 545 meters / 1,788 ft / 1,835 Roman feet. The central arena is an oval 287 ft long and 180 ft wide, surrounded by a wall 15 ft high, above which rose tiers of seating. The outer wall is estimated to have required over 100,000 cubic meters / 131,000 cu yd of travertine stone which were set without mortar held together by 300 tons of iron clamps.
The Colosseum is Capable of seating 50,000 spectators, was used for gladiatorial contests and public spectacles such as mock sea battles, animal hunts, executions, re-enactments of famous battles, and dramas based on Classical mythology. The building ceased to be used for entertainment in the early medieval era. It was later reused for such purposes as housing, workshops, quarters for a religious order, a fortress, a quarry, and a Christian shrine. It has been estimated that about 500,000 people and over a million wild animals died in the Colosseum games.

In 21st century it resides partially ruined because of break caused by earthquakes and stone-robbers. The Colosseum is an iconic symbol of Imperial Rome and its breakthrough achievements in earthquake engineering. It has close connections with Roman Catholic Church, as each Good Friday the Pope leads a torchlit "Way of the Cross" procession that starts around the Colosseum. The Colosseum is also represented on the Italian version of five-cent euro coin.