Zeyrek Mosque

This mosque was once the Byzantine church of the Pantokrator monastery, a vast twelfth-century imperial foundation built under the Komnenos dynasty as a church, hospital and mausoleum. It is the second-largest surviving Byzantine religious structure in the city after Hagia Sophia, formed of three linked chapels under separate domes. Restoration has revealed patches of its original marble floor and coloured glass. Set in a hillside district of old timber houses that is itself a heritage zone, it marks a key survival of Byzantine Constantinople.