The "Church of Holy Wisdom". Located in Constantinople and constructed by Justinian, it was built in 532. It is one of the most incredible works of architecture ever built, due to the illusion of space inside, and the apparently unsupported dome. It was tiled along all the walls with mosaic art depicting the lives of Christ and the Saints. It was converted to a mosque, and the mosaics painted over, after the Turks took Constantinople. It still stands today as a museum.