The best way to get to this part of town is to catch the Haliç (Golden Horn) ferry from Karaköy to Ayvansaray and walk up the hill along Dervişzade Sokak, turn right into Eğrikapı Mumhane Caddesi and then almost immediately left into Şişhane Caddesi. From here you can follow the remnants of Theodosius II's land walls, passing the Palace of Constantine Porphyrogenitus on your way. From Hoca Çakır Caddesi, veer left into Vaiz Sokak just before you reach the steep stairs leading up to the ramparts of the wall, then turn sharp left into Kariye Sokak and you'll come to the museum.
The building was originally known as the Church of the Holy Saviour Outside the Walls (Chora literally means 'country'), reflecting the fact that when it was first built it was located outside the original city walls constructed by Constantine the Great.
What you see today isn't the original church. Instead, it was reconstructed at least five times, most significantly in the 11th, 12th and 14th centuries. Virtually all of the interior decoration – the famous mosaics and the less renowned but equally striking frescoes – dates from c 1320 and was funded by Theodore Metochites, a poet and man of letters who was logothetes, the official responsible for the Byzantine treasury, under Emperor Andronikos II (r 1282–1328). One of the museum's most wonderful mosaics, found above the door to the nave in the inner narthex, depicts Theodore offering the church to Christ.
Today the Chora consists of five main architectural units: the nave, the two-storied structure (annexe) added to the north, the inner and the outer narthexes and the chapel for tombs (parecclesion) to the south. In 2013 a second major restoration commenced. This ongoing process is happening in stages, and involves closure of parts of the museum; the nave, two-storey annexes on the northern side of the building and most of the inner narthex have been completed, and work on the outer narthex and parecclesion were underway at the time of research.
Most of the interior is covered with mosaics depicting the lives of Christ and the Virgin Mary. Look out for the Khalke Jesus, which shows Christ and Mary with two donors: Prince Isaac Comnenos and Melane, daughter of Byzantine emperor Michael VIII Palaiologos. This is under the right dome in the inner narthex. On the dome itself is a stunning depiction of Jesus and his ancestors (The Genealogy of Christ). On the narthex's left dome is a serenely beautiful mosaic of Mary and the Baby Jesus Surrounded by her Ancestors.