The Apollon Municipal Theatre of Ermoupolis was built in 1864, by the French architect Chabeau. It is placed on Miaouli square, in the centre of Ermoupoulis, and constitutes a miniature replica of La Scala di Milan. It is made of white marble and limestone and has two floors. It also has many beautiful wall paintings and wooden tiers. This theatre was the first opera house in Greece. Until 1944, Italian operas were frequently presented there. Then the building was destroyed almost completely by the Germans
Today the theater hosts some of the major events in Syros such as theatrical performances, art exchibitions & a lot of international Festivals. Anima Syros & International Aegean Festival are some of the most important ones.