The Kaaba Located in Mecca, this stone structure, covered with a black cloth and known as the Kaaba, was originally home to the numerous deities of pre-Islamic Arabia. Cleansed by Muhammad, it became the sacred shrine of Islam and the destination of countless pilgrims undertaking the hajj. Part of that ritual involves circling the Kaaba seven times, as shown here in a photograph from 2013. (Ibraheem Abu Mustafa/Reuters/Landov)