Saudi Arabia will welcome one million people, including 850,000 from abroad, for the Hajj pilgrimage after two years of curtailed numbers due to the Covid-19 pandemic.
White-robed worshippers from across the world have packed the streets of Mecca as Islam's holiest city prepares to host the biggest Hajj pilgrimage since the coronavirus pandemic.
Banners welcoming the faithful, including the first international visitors since 2019, festooned squares and alleys, while armed security forces patrolled the ancient city, birthplace of the Prophet Muhammad.
"This is pure joy," Sudanese pilgrim Abdel Qader Kheder said in Mecca, ahead of the event expected to start on Wednesday.
"I almost can't believe I am here. I am enjoying every moment."
One million people, including 850,000 from abroad, are allowed at this year's Hajj after two years of drastically curtailed numbers due to the pandemic.
At least 650,000 overseas pilgrims have arrived so far in Saudi Arabia to converge on the holy city for several days of rituals in which they retrace the Prophet Muhammad's last pilgrimage, the authorities said on Sunday.
Pilgrims must first enter a state of purity, called ihram, which requires special dress and behaviour.
Men wear a seamless shroud-like white garment that emphasises unity, regardless of social status or nationality. Women must wear loose dresses, also white, exposing only their faces and hands.
Pilgrims are not allowed to argue or bicker and are prohibited from wearing perfume, cutting their nails, or trimming their hair or beards.
The first ritual requires walking seven times around the Kaaba, the large black cubic structure at the centre of Mecca's Grand Mosque.
Made from granite and draped in an heavily-embroidered cloth featuring verses of the Koran, the Kaaba stands nearly 15 metres (50 feet) tall.
The structure is said to have been first erected by Adam and then rebuilt by Abraham 4,000 years ago.
Pilgrims next walk seven times between two stone spots in the mosque.
They then move on to Mina, around five kilometres (three miles) away, ahead of the main rite of the pilgrimage at Mount Arafat.
The climax of the Hajj is the gathering on Mount Arafat, about 10 kilometres (six miles) from Mina, where it is believed that the Prophet Muhammad delivered his final sermon.
Pilgrims assemble on the 70-metre-high (230-foot) hill and its surrounding plain for hours of prayers and Koran recitals, staying there until the evening.
After sunset pilgrims head to Muzdalifah, halfway between Arafat and Mina, where they gather several dozen pebbles so they can perform the symbolic "stoning of the devil".
The last major ritual of the Hajj is back at Mina, where pilgrims throw seven stones at each of three huge concrete walls representing Satan.
The ritual is an emulation of Abraham's stoning of the devil at the three spots where it is said Satan tried to dissuade him from obeying Allah's (God) order to sacrifice his son, Ishmael.
After the first stoning, the Eid al Adha feast of sacrifice begins, marking the end of the Hajj. Sheep are slaughtered, in reference to the lamb that Allah provided for sacrifice instead of Ishmael.
Men then shave their heads or trim their hair while women cut a fingertip-length off their locks.
The pilgrims can then change back into normal clothing, returning to circumambulate the Kaaba and complete their stone-throwing rituals before heading home.