For Shi'ite Muslims, Ashura commemorates the martyrdom of Husain, Prophet Muhammad's grandson, in AH 61 (680 CE). Observed for 10 days from the first of the month of Ashura, the event is a time of great mourning. For Sunni Muslims, Ashura is a time to remember Noah's safe landing after the Flood and the Israelites liberation from Egypt under Moses. Observance begins at sunset of August 28, but special worship and prayers begin on August 29.
Description provided by Multifaith Calendar