Architects were able to place forty windows around the base of the dome. The Hagia Sophia is famous for the mystical quality of light that reflects everywhere in the interior of the nave, which gives the dome the appearance of hovering above the nave.

This design is possible because the dome is shaped like a scalloped shell or the inside of an umbrella with ribs that extend from the top of the dome down to the base. These ribs allow the weight of the dome to flow between the windows, down the pendentives, and ultimately to the foundation.