Millions of Shia Muslim pilgrims have gathered in Karbala (a holy city in central Iraq) to observe Ashura, one of the most significant dates in the Shia religious calendar. The occasion commemorates the death of Imam Hussein, grandson of the Prophet Muhammad, who was killed at the Battle of Karbala in 680 AD. The annual pilgrimage is among the largest religious gatherings in the world and holds deep spiritual and historical significance for Shia communities globally.