Zee Clicks's video: Istanbul day 2 Part II

The Hagia Sophia was built in the remarkably short time of about six years, being completed in 537 CE. Unusual for the period in which it was built, the names of the building’s architects—Anthemius of Tralles and Isidorus of Miletus—are well known, as is their familiarity with mechanics and mathematics. The Hagia Sophia combines a longitudinal basilica and a centralized building in a wholly original manner, with a huge 32-metre (105-foot) main dome supported on pendentives and two semidomes, one on either side of the longitudinal axis. In plan the building is almost square. There are three aisles separated by columns with galleries above and great marble piers rising up to support the dome. The walls above the galleries and the base of the dome are pierced by windows, which in the glare of daylight obscure the supports and give the impression that the canopy floats on air.