Istanbul was one of the most often besieged cities in the world and has always needed permanent water supplies. And as a result many underground cisterns were built during the Byzantine Empire. Water was brought to these big reservoirs from far away sources through aqueducts. It is still possible to see remains of a large aqueduct in Unkapani. This is called Bozdogan Kemeri (Aqueduct of Valens) and was built in 375 AD by the Emperor Valens. Because Turks have always preferred running water, after capturing the city from the Byzantines, they did not use cisterns properly. Most of them were usually converted into either small bazaars or storehouses. The largest and most ornate of these cisterns is Yerebatan Sarayi. In its construction, columns and capitals of earlier temples were used and this provides a very decorative appearance. This is why it is called saray which means “palace” in Turkish.
Yerebatan Sarayi was dug and built probably after 542 by Emperor Justinian I. There are 336 columns most of which are topped with Byzantine Corinthian capitals. The cistern is 70 m / 230 ft wide and 140 m / 460 ft long.
Between 1985-1988, the Municipality of Istanbul cleaned and restored it thoroughly and built a wooden walkway between the columns. In addition to that there are special effects presented by a light and sound show. By looking at the water level marks on the plaster walls which reach the height of the capitals, it is possible to understand that the cistern was very full in times gone by.
Two Medusa heads were used to form bases for two columns in a far corner of the cistern. The position in which they were placed suggests that the people who put them there were Christians and did not want to revere a god of a pagan period. The water inside the underground cistern is collected rain water. The carp in the water are decorative and an incidental protection against pollution. Some people even think that the Byzantines originally also raised fish in the cistern.
Built by Sultan Ahmet I as a part of a large complex, among the Turkish people it is called Sultan Ahmet Mosque. However, tourists fascinated with the beautiful blue tiles always remember it as the Blue Mosque. The complex consisted of a mosque, tombs, medreses, fountains, a health center, kitchens, shops, a bath, rooms, houses and storehouses.
A 19-year-old Sultan started digging ceremoniously in the presence of high officials until he was tired. Thus began the construction in 1609 which continued until it was finished in 1616. An interesting fact about Sultan Ahmet is that he ascended to the throne at the age of 14 as the 14th ruler and died only 14 years later. Being close to the Topkapi Palace, Sultan Ahmet Mosque was regarded as the Supreme Imperial Mosque in Istanbul. Even though the palace was left and the sultan moved to the Dolmabahce Palace, Sultan Ahmet Mosque shared this pride with the Suleymaniye Mosque.
The architect was one of the apprentices of Sinan, Sedefkar Mehmet Aga. He designed one of the last examples of the classical period’s architectural style.
The mosque is situated in a wide courtyard which has five gates. There is an inner courtyard next to the mosque with three entrances. The inner courtyard is surrounded by porticos consisting of 26 columns and 30 domes. The sadirvan in the middle is symbolic, because the actual ones are outside on the walls of the inner courtyard. There are three entrances to the main building, one from the inner courtyard and two from both sides of the building. There are four minarets at the corners of the mosque having three serefes each. The two minarets at the far corners of the courtyard have two serefes each. There are six minarets in all, each of which is fluted.
The interior of the mosque is a square with a width of 51.65 m / 170 ft and a length of 53.40 m / 175 ft covered by a dome. The main dome rests on four semi-arches and four pendentives. The diameter of the dome is 22.40 m / 73.5 ft and the height is 43 m / 141 ft. The four piers carrying the dome are called elephant legs as each has a diameter of 5 m / 16.4 ft.
There are 260 windows which do not have original stained glasses any longer. The walls all along the galleries are covered with 21 thousand 17C Iznik tiles having many flower motifs in a dominant blue color.
On summer evenings, generally beginning at 8:00 p.m., a sound-and-light show, which is worth seeing, is presented between the Blue Mosque and the Hagia Sophia. The languages of the show Turkish, English, French and German rotate daily with one each night.