The Church of Hagios Demetrios (St. Demetrius) is located in the center of Thessaloniki, close to Plaza Aristotle. It was built in the 5th century over ruins of Roman baths or a prison.
The church is dedicated to the patron saint of the city - St. Demetrius, who was born there. The church kept relics of the saint. Over the years it has been burnt and looted several times. In 1493, during the Ottoman, the period, the temple was converted into a mosque. In 1948 it was turned to its original form and purpose.
Dating from different ages during the existence of the church there are several preserved columns. In its basement there are the foundations of the first church. The church's holiday is celebrated on October 26, the date which is deemed that St. Demetrius have passed away. Part of the celebration is a procession, which exports the relics of the saint and visited by pilgrims from around the world.