architecturealliance: Catacombs of the great Byzantine Basilica of Hagios Demetrios of Thessaloniki
architecturealliance: Catacombs of the great Byzantine Basilica of Hagios Demetrios of Thessaloniki (629-634 AD). It is part of the Palaeochristian and Byzantine Monuments of Thessaloniki on the list of World Heritage Sites by UNESCO -- source link