Intense emotion, sacrifice and ancient ritual: last year more than 6,000 Emiratis joined the throng of three million making the gruelling pilgrimage to Mecca to perform rites such as circling the Kaaba, "stoning the devil" and standing vigil at Mount Arafat.
Now the Haj pilgrimage is set to be the focus of the British Museum's next major exhibition, Hajj: Journey to the Heart of Islam, opening in January and following shows on Afghanistan and Iran.
The Saudi Arabian deputy education minister, Faisal bin Abdulrahman Al Muammar, attended a special preview on Tuesday, where he said that he hoped the show would "bring about greater understanding of Haj for non-Muslims" as well as celebrating the tradition for everyone else.
For the project curator Qaisra Khan, a Muslim born and raised in the UK city of Manchester, putting the show together wasn't just an absorbing job - it was the catalyst for her own spiritual journey.
She had been on the Umrah, or lesser pilgrimage, but had never before performed Haj, which takes place on the last month of the Islamic year and dates back to the seventh century. With the encouragement of a colleague, she made the journey in October for the first time - bringing back suitcases of souvenirs that are to be displayed in a section of the exhibition dedicated to modern-day Haj.
"It's really difficult to put in a sentence," she explains, when asked how it felt to undergo such a momentous journey. "It's a very moving experience. You're in a barren landscape: no phones, no money - in Arafat, the most important part of the Haj, there are no shops - nothing. You're among the mountains of Saudi Arabia and you're completely on your own. You're surrounded by millions of people, but at that stage it's a matter of introspection."
To get there she flew from Heathrow airport to Cairo, taking an ancient route (albeit using modern modes of transport), via Jeddah and Medina. Once there, the rites to be performed are intensely physical: walking seven times around the Kaaba and seven times between the hills of Safa and Marwah, standing vigil at Mount Arafat, sleeping in the open air and throwing stones to symbolise defiance of the devil.
"It's a very arduous journey," Khan said. "Which is why these elements of being patient and not harming anybody" - Haj pilgrims must not quarrel - "really come into effect. You can't help but carry those further on in your life because it's such an intense experience."
When she came back, she said, "my whole view of the exhibition changed. They say that when you go on Haj it's due to an invitation by God, and my invitation must have been due that year."
There are plenty of surprising facts and colourful stories about Haj that are planned for the exhibition, which is going ahead with the co-operation of the Saudi government and will make use of loans from around the world. They include extracts from The Autobiography of Malcolm X (the American Muslim and black rights campaigner went on Haj in 1964) and the bottle that the explorer Richard Burton filled with holy water from the Zamzam Well in 1853.
The exhibition will also offer statistics about who Hajis are (westerners may be surprised to learn that the majority are not Arab, due in part to the prevalence of Islam in south-east Asia; Indonesia has the world's largest Muslim population). Its aim is to bring a fresh perspective on Islam to experts as well as the public.
Venetia Porter, the exhibition's chief curator, says initiatives designed to educate non-Muslims about Islam, are "absolutely crucial", adding: "There's too much [in the media] about Islam in a negative way, unfortunately. We want there to be a positive feeling."
As well as giving British Muslims a place in which they can "recognise themselves, and learn something new" about their faith, the curators have been filling in the gaps in academic research on Haj drawn from disparate sources of information.
According to Neil MacGregor, the museum's director, the show will also fulfil one of the institution's original goals, which is to examine the relationship between faith and society as seen in past shows such as Ancient Egyptian Book of the Dead and Buddhism across Asia.
On Haj, he says: "This is a worldwide phenomenon. And it's clearly a phenomenon that needs to be understood better than it actually is."
The exhibition itself will be divided into three sections: the journey; Mecca and the rituals; and what it means to be a pilgrim. These stories will be told through contemporary art, video, archaeological materials, historic photographs, textiles and other artefacts.
There are also tentative plans to take a smaller version of the exhibition on a Middle East tour after it closes in London next April. "We're in discussions but nothing is firm yet," says Porter.
Hajj: Journey to the Heart of Islam opens at the British Museum on January 26.