In Side there are the remains of a Roman theatre with a seating capacity of almost 20,000 spectators. It was built in the middle of the 2nd century AD. The structure has elements that distinguish it from other theatres built earlier. It was built not like the Hellenes - on the slope of a mountain, but in the Roman style - on a flat platform, the seats are held on vaulted arches, the arches themselves - on the foundation. The spectators entered the theatre through covered galleries and ascended to their row by stairs. The stage and vaults were decorated with statues and tiles. All that remains today are the masks of Tragedy and Comedy, and the broken-off heads of the Medusas scattered about the stage.
In Roman times, gladiatorial fights with predatory animals were organised here, as well as mock sea battles, for which the stage was filled with water. For safety reasons, a 1.5 metre high wall was built around the stage. In the V-VI centuries the theatre became a Christian temple.
Near the theatre in a semicircular building is an antique public toilet for 24 seats with sewage system.
