British Museum, London
The hajj – the once-in-a-lifetime pilgrimage of Muslims to Mecca – is very much a growth industry. In 1932, 20,000 pilgrims made the symbolic journey, the fifth pillar of Islamic obligation. This year the faithful will number more than three million (officials from the London Olympics have consulted with the Saudi authorities to see how they manage the annual miracle of traffic flow). One of the striking aspects of this eye-opening exhibition at the British Museum – the first British show devoted to what remains a mysterious journey among non-believers – is the way that the yearly mass migration invokes profound abstract geometries.
The anti-clockwise currents and eddies of human bodies around the great black stone of the Ka'bah, each pilgrim shuffling to complete the necessary devotional seven laps, is a gift to time-lapse photography. You come away with perfect cubes and the circular motion of a white-robed tide of humanity imprinted on your retina. The sight, even on film, of the weeping millions on the Plain of Arafat, every contour of the central mountain moving with bodies from across the globe, is perhaps the most powerful spectacle of the physical attraction of faith the world has to offer.
The exhibition reminds you at every turn that no other religion has quite the geographical pull of Islam. Every time a Muslim turns to pray to Mecca, this sacred cartography is invoked. The concentric rings of orderly submission gesture to an all-powerful centripetal force. The Saudi artist Ahmed Mater Al-Ziad makes the obvious but perfectly executed analogy of magnetism to describe this global force field. In one corner of the show he has recreated his celebrated piece in which a black cube of a magnet draws its attendant iron filings into hajj-like patterns of devotion on a sheet of white paper. Some of the chips of metal lie prostrate; others are held quivering upright.
Idris Khan, the young Birmingham-born artist, has created two similarly simple pieces. At the entrance to the old Reading Room, which houses the linear progression of the exhibition, he has placed 49 cubes of black marble, each face sandblasted with a Qur'anic verse. Even among the totem poles and statuary under Norman Foster's geodesic roof, the blocks have a monumental quality that calls to mind American minimalism – a Donald Judd for the devout. Bookending the show is another piece by Khan called I Was Here for You and Only You, in which devotional mantras and spiritual questions – "Are you leaving as you had come?", directed to pilgrim and gallery-goer alike – have been painstakingly applied with a child's rubber stamp set, like thousands of black spokes of a wheel around the inevitable hub.
In taking the commission, Khan, of Welsh and Pakistani parentage, described how, as a mostly lapsed Muslim, he was moved by the life-changing effect of the hajj on his father. His two pieces are a nice testament to some of that paternal emotional mystery. The hand-printed piece is displayed alongside a taped loop of British Muslims talking about their experience of hajj. The Yorkshire and home counties accents are inflected with unashamed awe and wonder. "I felt like I was moving toward a centre of silence," says one; "You feel at a new level of closeness to Him," says another. At the Plain of Arafat, many say, they were reminded, in the 45-degree heat, and in the midst of millions, of how they would leave this world alone. These voices in the dark become hypnotic, fading to the mantras of Khan's devotional Spirograph: "What am I going to sacrifice to God, in my life?" they ask.
It is hard to distinguish between these contemporary voices and some of the expressions of the hajj experience noted in previous centuries. The pilgrimage in this sense is not just a geographical journey but also a temporal one, a marking of ancient footsteps. The first part of the show organises itself loosely around the four main routes to Mecca that were established in the years after the prophet Muhammad's death. The earliest hajj relics, on camel bone, are from the road established by Zubayd, wife of Harun al-Rashid of Arabian Nights fame. The road was constructed through what is now Iraq, with staging posts and reservoirs, at the turn of the 9th century AD. Most pilgrims came from the Middle East – from Cairo, Damascus, Baghdad and Basra – but there were also, even by the 11th century, movements of people from south-east Asia, west Africa and southern Europe.
Several of the exquisitely illustrated records and journals of the period suggest a kind of carnival spirit among those early pilgrims, travelling overland in caravans, a mix of God-fearing humanity and gossipy storytelling that might have been recognisable to Chaucer. This spirit is retained in the jerky newsreels of the earlier part of the 20th century with the faithful piling excitedly on to trains, right up to the present day, where the spiritual quest is equally a great family adventure, as recounted in the recent school diary of a north London schoolgirl, included in the show.
If this kind of spirit comes as a surprise to some, it is partly because the hajj has always been off-limits to non-believers. To make this point, a copied motorway sign from the holy city suggests an audience division into Muslims and non-Muslims; infidels, it suggests, are required to take the next exit. No British traveller dared to make the hajj before the indefatigable Victorian explorer Richard Burton, who disguised himself as a pilgrim in 1853 to write a bestselling book about his adventures; later, more authentic converts included Lady Evelyn Cobbold who became the first British woman to perform the hajj, in 1933, as she noted in passing in a wonderful preserved letter to her grandson, ("it seems that I have always been a Moslem," she suggested, aged 65).
Though an intimate part of the lives of many modern Britons, the pilgrimage remains in many senses a guarded world, which makes the treasures and curiosities collected here – many borrowed from Riyadh and beyond – a unique kind of insight. Neil MacGregor and his team at the British Museum, including Venetia Porter, curator of this exhibition, have, for a decade now, been on an impassioned quest themselves to shed light on some of the more misunderstood history and rituals of the contemporary world and to find the shared humanity in them. Once again, it is worth commending these boundless efforts at cultural diplomacy, and sheer determined curiosity, that allow us all to enjoy the detail and scope of a story that is to many a closed book.
Members of Guardian Extra are invited to an evening viewing of the exhibition followed by a two-course meal plus a curator's talk and Q&A session in the British Museum's Great Court restaurant. The event takes place on Friday 3 February at 5.30pm. For more information, go to guardian.co.uk/extra