Ashura (Arabic: عَاشُورَاء, ʿĀshūrāʾ, [ʕaːʃuːˈraːʔ]) is a day of commemoration or mourning in Islam. It occurs annually on the 10th of Muharram, the first month of the Islamic calendar. Among Shia Muslims, Ashura is observed through large demonstrations of high-scale mourning as it marks the death of Husayn ibn Ali (a grandson of Muhammad S.A.W.), who was beheaded during the Battle of Karbala in 680 CE. Among Sunni Muslims, Ashura is observed through celebratory fasting as it marks the day of salvation for Moses and the Israelites, who successfully escaped from Biblical Egypt (where they were enslaved and persecuted) after Moses called upon God's power to part the Red Sea. While Husayn's death is also regarded as a great tragedy by Sunnis, open displays of mourning are either discouraged or outright prohibited, depending on the specific act.
In Shia communities, Ashura observances are typically carried out in group processions and are accompanied by a variety of rituals ranging from weeping and shrine pilgrimages to the more controversial acts of self-flagellation and chest-beating called Tatbir which is partially allowed due to either being a mock-up of the war or by risking suicide.