What is the shape of the Colosseum?

The Colosseum is oval in shape. More precisely, its plan is elliptical: its long axis measures about 189 metres and its short axis about 156 metres.

This form came from the Roman amphitheatre design, essentially two theatres joined back to back. Unlike a conventional theatre, whose seating usually forms a semicircle around a stage, an amphitheatre surrounds a central arena. The Colosseum’s continuous oval seating allowed spectators to watch contests from every side.

The central arena was also elliptical, measuring roughly 83 by 48 metres. It originally had a wooden floor covered with sand, while the underground hypogeum later housed animals, gladiators, scenery, elevators, and machinery beneath it.

“Circular” is a common wrong answer because the building curves continuously and looks round from a distance. However, a circle has equal dimensions in every direction; the Colosseum is longer from end to end than across its width. “Oval” is the everyday English term, while “elliptical” is the more precise architectural description.