Engineering Perfection

The Colosseum was not just a stadium. It was a piece of technology that modern architects still admire:

• 80 entrances let the entire crowd exit in about 15 minutes — better crowd flow than most modern stadiums
• A retractable velarium (awning) shaded spectators, hauled into place by a large crew of Roman sailors
• The hypogeum below the floor used hidden shafts and lifts to raise animals and gladiators dramatically into view

In the early years the arena floor could even be flooded for mock naval battles, though engineers still debate exactly how it was done.