Amphitheater in Trier

You're standing at the Trier Amphitheater, a Roman arena built in the second century AD. Take a look at the lie of the land. The Romans cleverly set this arena into the slope of the Petrisberg hill, so they didn't have to prop up all the seating with man-made structures. The outer ring is roughly 140 by 120 meters, and around twenty thousand spectators could fit inside.