The dome of Hagia Sophia has spurred particular interest for many art historians, architects and engineers because of the innovative way the original architects envisioned it. The dome is carried on four spherical triangular pendentives, one of the first large-scale uses of them. The pendentives are the corners of the square base of the dome, which curve upwards into the dome to support it, restraining the lateral forces of the dome and allowing its weight to flow downwards.[183][184] It was the largest pendentive dome in the world until the completion of St Peter's Basilica, and has a much lower height than any other dome of such a large diameter.