Explainer: What is the Haj pilgrimage and what does it mean for Muslims?

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

The Haj 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.

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

The pilgrimage draws Muslims from around the world to Makkah, in Saudi Arabia, where they walk in the footsteps of the Prophet Muhammad (peace be upon him) and retrace the journey of Ibrahim (peace be upon him) and Ismail (peace be upon him).

As related in the Holy Quran, Ibrahim (peace be upon him)is called upon to sacrifice his son Ismail (peace be upon him) as a test of faith, but God stays his hand at the last moment. Ibrahim and Ismail (peace be upon him) later are said to have built the holy Kaaba together.

The holy Kaaba was a centre for polytheistic worship among pagan Arabs until the arrival of Islam in the 7th century, when the Prophet Muhammad (peace be upon him) consecrated the site and inaugurated the Haj.

Muslims do not worship the holy Kaaba, a cube-shaped structure covered in a black, gold-embroidered cloth, but view it as their most sacred place and a powerful symbol of unity and monotheism. No matter where they are in the world, Muslims face toward the Kaaba during their daily prayers.

The Haj has been held every year since the time of the prophet, even through wars, plagues and other turmoil.

In 2020, amid worldwide coronavirus lockdowns, Saudi Arabia limited the pilgrimage to a few thousand citizens and local residents. This is the first year it returns to full capacity.

Some pilgrims spend their whole lives saving up for the journey or wait years before getting a permit, which Saudi authorities distribute to countries based on a quota system. Travel agents offer packages catering to all income levels, and charities assist needy pilgrims.

Pilgrims begin by entering a state of spiritual purity known as “ihram.” Women forgo make-up and perfume and cover their hair, while men change into seamless terrycloth robes. The garments cannot contain any stitching, a rule intended to promote unity among rich and poor.