The Colosseum
The amphitheatre, inaugurated in AD80, was named after the colossal statue of Nero that stood beside it. It could accomodate more than 50,000 spectators who sat on one of the three levels depending on their status. To celebrate victory over the Dacians, Trajan held games here that lasted for 117 days, during which 9,000 gladiators and 10,000 beasts fought to the death. Gladiators were professional and sometimes spared if they'd put up a good enough scrap, not so the poor misfortunates pitched against them for whom the fight was to the end.
This shot, looking south, was taken from the Piazza del Colosseo.