The Colosseum is the largest amphitheater built during the Roman Empire. It is considered one of the greatest works of architecture and engineering in ancient Rome.  This magnificent building was paid for largely by the 50,000kg of gold and silver taken during the sacking of Jerusalem. Construction was started by Vespasian in the year 70 and completed by his son, Titus (https://www.jeffbondono.com/TouristInRome/EmperorTitus.html) , 10 years later. Vespasian's younger son, Domitian then made improvements and expansions up until the year 96.