St Demitrius Church

St Demitrius Church in Thessaloniki, Greece is known for the crypt/catacomb underneath it. It also holds the remains of St Demitrius as well as two other saints. St Gregorius Callides and St Anyasia. As with many churches of it's age in the region,  it was for a time used as a mosque. During this time, holes were oft3n drilled into the walls in an attempt to destroy the frescos and mosaics. Also, as witany structures, it was built on top of the remains of other, older structures.