Eid ul-Adha (Arabic: عيد الأضحى ‘Īd al-’Aḍḥā) is a religious festival celebrated by Muslims and Druze worldwide as a commemoration of Ibrahim's (Abraham's) willingness to sacrifice his son Ismael for Allah. It is one of two Eid festivals that Muslims celebrate. Like Eid ul-Fitr, Eid ul-Adha begins with a short prayer followed by a sermon (khuṭba). It is also called the bigger Eid because it lasts a day longer than Eid ul-Fitr.
Eid ul-Adha is four days long and starts on the 10th day of the month of Dhul Hijja (ذو الحجة) of the lunar Islamic calendar. This is the day after the pilgrims in Hajj, the annual pilgrimage to Mecca in Saudi Arabia by Muslims worldwide, descend from Mount Arafat. It happens to be approximately 70 days after the end of the month of Ramadan.