Arènes de Lutèce
This Roman amphitheater, designed as a theater and circus, was almost completely destroyed by barbarians in AD 280. The site was rediscovered in 1869, and you can still see part of the stage and tiered seating. Along with the remains of the baths at Cluny, the arena constitutes rare evidence of the powerful Roman city of Lutetia that flourished on the Rive Gauche in the 3rd century. Today it's a favorite spot for picnicking, pickup soccer, or boules.