* Eid al-Adha, one of Islam's two main festivals, marks the climax of the annual hajj pilgrimage, when Muslims slaughter animals - to commemorate the willingness of Ibrahim, or Abraham, to sacrifice his son on God's command - often distributing meat to the poor. Copyright 2025 Thomson Reuters.

Large numbers of Muslims converge once a year on Saudi Arabia to unite in a series of religious rituals and acts of worship as they perform the Hajj, the pilgrimage that is one of the pillars of Islam.

Here is a look at the hajj, one of the largest mass gatherings in the world, which starts in Saudi Arabia on Wednesday.