Muharram marks the first month of the Islamic calendar. Observed by both the Shia and the Sunni Muslims, Muharram marks the anniversary of the battle of Karbala, in which Imam Hussein ibn Ali, the grandson of prophet Muhammad, was killed by the second Umayyas caliph Yazid I and his forces. Muharram marks the yearly mourning month of the Muslims, when they commemorate the incident.
The tenth day of Muharram is referred to as Ashura. It literally means the "Tenth" in Arabic and is the tenth day of Muharram, when Imam Hussein ibn Ali was killed. Muslims across the world observe the month in utmost sorrow and pain and choose to refrain from any celebrations and festivities. Many of them also fast during the tenth day of Muharram or Ashura. In Sunni Islam, Ashura is also known to mark the day that Moses and the people of Israel were saved by God from Egypt's Pharaoh by parting the Red Sea to make a path in it. Other commemorations include Noah leaving the Ark and Muhammad's arrival in Medina.
Click through to see pictures of people across the world observing Muharram this year.
Shiite worshippers beat themselves with chains as a sign of grief for Imam Hussein during the Muslim month of Muharram, in front of the holy shrine of Imam Hussein, seen in the background in Karbala, south of Baghdad, Iraq. (Source: AP)