The Roman Colosseum
The Flavian Amphitheatre in Rome, completed in 80 AD under Emperor Titus and capable of seating some 50,000 spectators.
Vespasian began the Colosseum around 72 AD, funding it partly with plunder from the sack of Jerusalem after the Jewish War, and his son Titus opened it with a hundred days of games. Beneath the arena floor, a warren of tunnels and lift shafts — the hypogeum — hoisted gladiators, scenery, and wild animals up through trapdoors, and early in its life the arena could even be flooded for staged naval battles, or naumachiae. After centuries of earthquakes and stone-robbing left it half a ruin, it now stands as Rome's most recognizable monument. See our article on the Roman Colosseum.
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