Eid ul-Adha is second in the series of Eid festivals that Muslims celebrate across the world. It is also referred to as the "Big Bayram" (from Turkish) or "Big Feast." Eid ul-Adha is known as Hari Raya Haji in Singapore and Malaysia, and Tabaski in West Africa. In India, the animal used most often for sacrifice is the goat - which is why the occasion is spoken of in Urdu language as Bakrid or Eid-e-Qurban.

It is celebrated on the 10th day of the month of Dhul Hijja of the lunar Islamic calendar, after Hajj, the annual pilgrimage to Makkah in Saudi Arabia.

Muslims all over the world sacrifice animals in remembrance to the sacrifice offered by prophet Abraham thousands of years ago. Abraham (the father of all 3 big religions), who was in his late life was commanded by GOD to sacrifice his only son Ismael. Abraham didn't hesistate and prepare to sacrifice his only son and heir for the will of GOD. Prophet Ismael, his son willingly agreed to be sacrificed to show his obeidience to GOD. At the last minute, GOD replaced Ismael with the lamb that Abraham sacrificed.
The idea is to fully submit oneself to the will of GOD and to sacrifice the dearest thing for GOD's sake.

Do remember poor people and be generous to them, do ur qurbani and remember 1/3 belongs to needy, 1/3 to neighbors and relative and rest is yours.