Eidul Adha is the celebration of sacrifice. It is to remember the spirit of Prophet Ibrahim and how he was willing to sacrifice his son Ismail to show his obedience to Allah.
Muslims all around the world will celebrate this day, although it has particular significance for pilgrims who at this time will be completing the Hajj pilgrimage in Makkah. The day begins with a sacrifice of an animal in commemoration of Prophet Ibrahim’s sacrifce of a lamb in place of his son. When this is done, 1/3 of the meat goes to the needy people, 1/3 is given to neighbors and friends, and 1/3 stays with your family.