What festival or custom celebrates or observes hajj?

The festival that celebrates the completion of Hajj is Eid al-Adha, also known as the Festival of Sacrifice. It occurs on the 10th day of Dhu al-Hijjah, immediately following the Hajj pilgrimage. During this time, Muslims around the world commemorate the willingness of Ibrahim (Abraham) to sacrifice his son in obedience to God by performing animal sacrifices, sharing the meat with family and the less fortunate, and engaging in communal prayers. This festival highlights themes of sacrifice, charity, and community.