The sacred cloth at the center of the Hajj pilgrimage

During the Hajj pilgrimage, Muslims go around the cube-like sacred structure, the Kaaba, which is covered with a black cloth, the kiswah. MASTER/Moment via Getty Images

As Muslims gather for the annual pilgrimage of Hajj in Mecca, Saudi Arabia, they will circle around the “Kaaba,” a black cube draped in gold-embroidered cloth. A ceremonial textile – known as the “kiswah” – covers the Kaaba, around which Muslims will walk seven times in a ritual known as “tawāf.” It is the central act of the annual pilgrimage.

The Kaaba itself is a roughly cubic gray granite structure about 43 feet tall, which Muslims believe was established by the Prophet Abraham – Ibrahim in Arabic – and his son Ishmael as a place of monotheistic worship in antiquity. The Kaaba is empty inside, with no altar, idol or relic on display.