Built in the 3rd century, the El Jem amphitheatre could hold nearly 35,000 spectators. A UNESCO World Heritage site, it remains one of the best-preserved colosseums in the world.
You can wander freely, from the tiers to the underground passages where gladiators and wild animals once waited. The nearby museum holds superb Roman mosaics.
El Jem is easy to visit from Sousse, Monastir or Hammamet, often combined with Kairouan. The site also hosts a symphonic music festival in summer.