Magnificent and covered in mosaics, this five-aisle basilica is Greece's largest church and a powerful tribute to the patron saint of Thessaloniki. It was rebuilt and restored from 1926 to 1949, with attention to preserving the details of the original; the marks left by a fire can still be seen throughout. In the 4th century, during the reign of Emperor Galerius, the young, scholarly Dimitrios was preaching Christianity in the coppersmith district, in contravention of
an edict. He was arrested and jailed in a room in the old Roman baths, on the site of the present church. While he was incarcerated in AD 303, Dimitrios gave a Christian blessing to a gladiator friend named Nestor, who was about to fight Galerius's champion, Lyaios. When Nestor fought and killed Lyaios, after having made Dimitrios's blessing public, the enraged Galerius had Nestor executed on the spot and had Dimitrios speared to death in his cell. His Christian brethren were said to have buried him there. A church that was built on the ruins of this bath in the 5th century was destroyed by an earthquake in the 7th century. The church was rebuilt, and gradually the story of Dimitrios and Nestor grew to be considered apocryphal until the great 1917 fire burned down most of the 7th-century church and brought to light its true past. The process of rebuilding the church uncovered rooms beneath the apse that appear to be baths; the discovery of a reliquary containing a vial of bloodstained earth gave credence to the idea that this is where St. Dimitrios was martyred. You enter through a small doorway to the right of the altar. Work your way through the crypt (which tends to close a little earlier than the church itself), containing sculpture from the 3rd to 5th century AD and Byzantine artifacts. The church's interior was plastered over when the Turks turned it into a mosque, but eight original mosaics remain on either side of the altar.