Kirmasti Cistern is a Middle Byzantine cistern located a short distance north of the Fatih Mosque complex (the site of the former Church of the Holy Apostles). The remains of this cistern are now 20 by 20 meters, with a height of 10 meters. While it currently has nine columns (three rows of three columns) spaced 3.90 meters apart supporting 17 vaults, it probably originally had 16 columns (four rows of four columns). The original columns were removed during construction at the site in 1964, while a row of columns was damaged in 1997. Only three of its original Ionic impost capitals remain; the other six capitals and their columns were replaced by concrete. The cistern has beveled corners and its walls are covered with hydraulic plaster. Its arches also have recessed brick masonry. It perhaps dates to the 12th century.