What is the Hajj pilgrimage and what does it mean for Muslims?

Over 2 million Muslims will take part in this week's Hajj pilgrimage to the holy city of Mecca in Saudi Arabia, as one of the world's largest religious gatherings returns to full capacity following years of coronavirus restrictions.

Over 2 million Muslims will take part in this week's Hajj pilgrimage to the holy city of Mecca in Saudi Arabia, as one of the world's largest religious gatherings returns to full capacity following years of coronavirus restrictions.

The Hajj is one of the five pillars of Islam, and all Muslims are required to undertake it at least once in their lives if they are physically and financially able to do so. For the pilgrims, it is a profound spiritual experience that wipes away sins, brings them closer to God and highlights Muslim unity.

For the Saudi royal family, which captured Mecca in the 1920s, organizing the pilgrimage is a major source of pride and legitimacy. Authorities have invested billions of dollars in modern infrastructure, but the Hajj has occasionally been marred by tragedy, as in 2015, when over 2,400 pilgrims died in a stampede.

Here's a look at the pilgrimage, which begins on Monday, and its meaning.

The pilgrimage draws Muslims from around the world to Mecca, in Saudi Arabia, where they walk in the footsteps of the Prophet Muhammad and retrace the journey of Ibrahim and Ismail, or Abraham and Ishmael as they are known in the Christian and Jewish traditions.

As related in the Quran, Ibrahim is called upon to sacrifice his son Ismail as a test of faith, but God stays his hand at the last moment. Ibrahim and Ismail later are said to have built the Kaaba together. In the Christian and Jewish traditions, Abraham nearly sacrifices his other son, Isaac, on Mount Moriah, which is associated with a major holy site in Jerusalem.

The Kaaba was a center for polytheistic worship among pagan Arabs until the arrival of Islam in the 7th century, when the Prophet Muhammad consecrated the site and inaugurated the Hajj.