Ashura
Islamic
Ashura is commemorated as the day that Allah parted the Red Sea for Moses and his followers, the Israelites, to escape from the tyranny of the Egyptian pharaoh. In the years after the prophet Muhammad's death, his grandson al-Husayn (along with others in his family) was martyred on Ashura, so this is commemorated at this time as well, esp. among the Shi'a.
Date details: Tenth of Mu?arram, the first month of the Muslim calendar (Gregorian).