IN PICTURES: Two million Muslims begin Hajj 2018 pilgrimage

More than two million Muslim faithful are beginning their Hajj pilgrimage on Sunday.

The pilgrimage represents one of the five pillars of Islam and is required of all able-bodied Muslims once in their life.

In recent weeks, the faithful have arrived in Mecca from across the world, all chanting "Labayk Allahuma Labayk," or "Here I am, God, answering your call. Here I am."

READ ALSO: Hajj explained: Your simple guide to Islam’s annual pilgrimage

Muslims believe the Hajj retraces the footsteps of the Prophet Muhammad, as well as those of the prophets Ibrahim and Ismail.

Adult Muslims are required to perform Hajj at least once in lifetime if they have the physical and financial ability.

Men attending the hajj dress in only terrycloth, seamless white garments meant to represent unity among Muslims and equality before God. Women wear loose clothing, cover their hair and forgo makeup and nail polish to achieve a state of humility and spiritual purity.

After prayers in Mecca, pilgrims will head to an area called Mount Arafat on Monday, where the Prophet Muhammad delivered his final sermon. From there, pilgrims will head to an area called Muzdalifa, picking up pebbles along the way for a symbolic stoning of the devil and a casting away of sins that takes place in the Mina valley for three days.

At the hajj's end, male pilgrims will shave their hair and women will cut a lock of hair in a sign of renewal for completing the pilgrimage. Around the world, Muslims will mark the end of hajj with a celebration called Eid al-Adha. The holiday, remembering Ibrahim's willingness to sacrifice his son, sees Muslims slaughter sheep and cattle, distributing the meat to the poor.

While a holy, once-in-a-lifetime experience for pilgrims, the hajj is by no means an easy journey. The temperature in Mecca and Mina will be around 42 degrees Celsius.

The first day of hajj is 8 Zil Hijjah, the last month of the Islamic calendar. The holy journey requires the pilgrim to perform ten rituals before and during hajj.

For the basic steps you may want to know about hajj, click here.

(With AP. Images: AFP and AP)