Muslimpress: Shia Muslims from across Iraq and the Muslim world descend on city to mark the death of Imam Hussein, Al - Jazeera reported. Millions of Shia Muslims, beating their heads and chests in mourning, have packed the Iraqi city of Karbala for the culmination of one of the world's largest religious events. The faithful have for days been streaming through the golden-domed mausoleum of Imam Hussein, Prophet Muhammad's grandson who was killed in 680 AD. Many in the sea of black-clad devotees swarming the shrine walked days to reach Karbala, sometimes from cities as far as Basra, about 500km away by road. Baghdad and much of the country south of Baghdad come to a standstill in the days preceding Arbaeen, as parts of the motorway are reserved for walking pilgrims and for authorized vehicles only. Arbaeen, which means "40" in Arabic, is an observance that peaks on the 40th day after the anniversary of Hussein's death, but the pilgrimage takes place over several days running up to it.