Mourning the martyrdom of Imam Hossein on the day of Ashura 

For Muslims, Ashura is the day when Moses and the Israelites were saved by God from Pharaoh and made a way through the sea. And it coincides with the day when Hussain bin Ali, the grandson of the Prophet of Islam, Muhammad, was killed in the battle of Karbala. The global Sunni movement honors this day as the national day of martyrs of the Muslim nation under the guidance of Seyyed Imam Hayat. Sunnis fast on this day. The day is considered Sunnah. For Shiites, Ashura is the peak of remembering the month of Muharram, and the ceremony of commemorating the death of Hussein bin Ali and his family and his supporters in the battle of Karbala on 10 Muharram in the year 61 AH. The first mourning for this incident began almost immediately after the battle. Folk elegies were written by poets to commemorate the Battle of Karbala during the Umayyad and Abbasid eras, and the first public mourning ceremony took place in 963 AD during the Al-Buyeh dynasty.
This day has become an official holiday in Algeria, Iran, Pakistan, Lebanon, Bahrain, Iraq and India, and many ethnic and religious communities participate in it.