The flag is flown on the Ismaili Jamatkhana, a place for congregational worship for Ismaili Muslims during the festive occasions.[32] The Ahmadiyya movement also employs an official flag (Liwaa-i Ahmadiyya) with black and white colors, first hoisted in 1939.[33] Mirza Tahir Ahmad, the fourth caliph of the Ahmadiyya Caliphate, explained the symbolism of the colours black and white in terms of the concept of revelation and prophethood.[34] Muslim African-American religious movement Nation of Islam deploys an official flag known as "The Flag of Islam" which symbolizes universal peace and harmony.[35]