According to tradition, Abraham and his son Ishmael built (or perhaps rebuilt) a simple cubelike structure in what came to be the center of the city of Mecca. During Muhammad’s time the Ka’aba was a relatively small structure, about fifteen feet tall, with a black stone, the size of a bowling ball, of (perhaps) meteoric origin built into one of its corners. Rebuilt several times since Muhammad’s day, the Ka’aba now stands about forty-three feet high, with irregular sides ranging from thirty-six to forty-three feet. During Muhammad’s lifetime, the building is said to have housed some 360 idols. In 630, Muhammad cleansed the Ka’aba, and it has since remained empty except for some lamps. Its holiness as a symbol of divine presence derives largely from its associations with the lives of Abraham and Muhammad.