In Side preserved remains of the Roman theater, which seats nearly 20,000 spectators. It was built in the middle of the II century AD In construction, there are elements that distinguish it from other theaters built earlier. It is built quite differently, like the Greeks - on the mountainside, and a Roman-style - on a level surface, the seat stay on the vaulted arches, arches themselves - on the foundation. The audience consisted of him through the cloisters and climbed a series of stairs. The scene and the vaults were decorated with statues and tiles. All that remains today - a mask of tragedy and comedy, cleaved the head of Medusa, scattered around the scene.

In Roman times there were organized gladiator fights with predatory animals, and staging naval battles, which the stage was filled with water. For safety around the stage it was built a wall height of 1, 5 m. In V-VI centuries theater became a Christian temple.

Near the theater in a semicircular building is the ancient public toilet for 24 people with sanitation.