Eid ul-Adha, or the Feast of Sacrifice, is celebrated by Muslims around the world as an important holiday over a three-day period. Most Muslims will participate in special prayer called Solat ul-Eid in several large Islamic mosques and places of worship around the world.
The Feast of the Sacrifice dates back to the historical event in which the prophet Abraham (a.s) was commanded by Allah (s.w.t), in a dream to sacrifice his son Ismail (a.s). But while he was sacrificing his son, Allah (s.w.t) sent the angel Gabriel and replaced Ismail (a.s) with a huge ram. …(This story is mentioned in chapter 37 of Al-Quran)
Eid ul-Adha has special significance because the Day of Sacrifice marks the culmination of the Hajj or pilgrimage, which is one of the fifth pillar of Islam. This annual pilgrimage to Mecca and Medina in Saudi Arabia is compulsory upon every Muslims men and women who are physically and financially capable of performing it once in a lifetime.