Hypogeum of the Amphitheatre of El Jem, an archeological site in the city of El Djem, Tunisia. This spot of the hypogeum is the place where the gladiators went up to the gate of the arena when the games started. The amphitheatre, a UNESCO World Heritage Site since 1979, was built around 238 AD, when the modern Tunisia belonged to the Roman province of Africa. It is the third biggest amphiteatre and one of the best preserved Roman ruins in the world with capacity for 35,000 spectators within 148 metres (486 ft) and 122 metres (400 ft) long axes and unique in Africa.. Learn more.