Most people know at least something about the Roman Colosseum, but it’s impossible to gauge the enormous (some might even say “colossal”) size of this structure.
Contrary to popular imagery of cruel emperor Nero presiding over blood sports in this arena, the Colosseum wasn’t even started until after Nero’s death, although it is tangentially connected to him. After the great fire of Rome, Nero had used a newly unoccupied portion of the city not far from the Roman Forum to build a extravagant “Domus Aurea” or Golden House for himself. Not surprisingly, this didn’t exactly improve his standing with the citizens of Rome.
After Nero’s death, there was a brief period of chaos in Rome, as different factions struggled for control (I won’t get into the Year of the Four Emperors here, but you can click on the hyperlinks for some excellent resources about it. Long story short: being emperor during that year was one of the most dangerous jobs in the entire Empire. You were almost certainly safer fighting on the front lines of the most unstable part of the frontier). When the smoke finally cleared, a successful general name Vespasian seized control of the empire. Eager to win the public’s goodwill, Vespesian built a huge public ampitheater near the site of Nero’s Golden House.
Tragically, since both Vespasian and his son and succesor Titus were generals who fought against Jerusalem during the Jewish revolts of the first century, and treasure stolen from the Jews was used to build the Colosseum.
Originally called the Flavian Ampitheater (after the Flavian dynasty started by Vespasian), the structure was later renamed the Colosseum as sort of a nickname, referencing the enormous statue which used to stand near the site (the name of which, in turn, was referencing yet another statue, the Colossus of Rhodes).
During the early years of the Colosseum, it was occasionally filled in with water, and mock naval battles were fought in it. However, Titus’s brother and successor Domitian decided to construct tunnels underneath the arena instead, trading the occasional in-stadium naval battle for the ability to bring fighters, animals and props through trap doors in the floor.