The Theatre Dionysus, built in the 6th century BC, is the oldest open-air theatre. There have been countless tragic works of Aesculus, Sophocles and Euripides, and Aristophanes, in this theater that can accommodate 17,000 people. The theater is built on a hillside, and it is astoundingly large as it is condensing the beauty of the world. In ancient Greece (especially Athens), watching tragedy is not only the main artistic activity of the public, but also an important part of the life of the city-state.