The sanctuaries of Mecca and Medina are the holiest sites of Islam. As part of the Hajj which is one of the five pillars of Islam, pilgrims perform rituals at Mecca and other nearby sites.[5] On his expeditions from 1861 to 1881, Sadiq photographed the interiors and exteriors of sites on the Hajj pilgrimage route as well as at Medina.