CAPTION CORRECTION © Licensed to London News Pictures. 20/11/2016. Muslims take part in the annual Arbaeen procession,  which marks a sacred Shia Muslim ritual. Arbaeen, also known as Chehlum, commemorates the end of the 40-day mourning period after the killing of Imam Hussein, the Prophet Muhammad's grandson, in a battle in 680 AD. His martyrdom is considered a defining event in the schism between Sunni and Shia Muslims. London, UK. Photo credit: Ray Tang/LNP
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