Part of the joy of pilgrimage is a spirit of community that comes from identifying with something bigger than oneself. The pilgrim who sets out solo shares a bond with others who journey on the same path: the aches, the pains and the triumphs. "The experience is very much about helping other pilgrims," says Abbot Christopher Dillon of Ireland's Glenstal Abbey, who walked the rugged Camino last year and hosts occasional pilgrims at his monastery in County Limerick. "There is great companionship on the road." That's the whole point of the Volksmarches, the communal hikes in Germany that attract thousands every year. The preservation of generational bonds is at the heart of the pilgrimages made to the battlefields of Europe, where families go to honor forebears they never knew but will never forget.

And yet each pilgrim is utterly alone, because a pilgrimage is a trip not just to a physical place but also into a person's soul. So one can travel to Dublin to celebrate Bloomsday, be surrounded by thousands of other Ulysses lovers, and yet be absolutely alone with one's own epiphanies about James Joyce's masterwork.

The traditional may argue that only the religious creature is a true pilgrim, but as Phil Cousineau, the author of The Art of Pilgrimage, says, "The phenomenon of pilgrimage tends to hold up a mirror to what is sacred for the times." The world has changed, and so has pilgrimage. There will also always be those who label it foolishness, whether you embark with a belief in an unseen God's promise of salvation or in the power of a pair of devilish stilettos, as the amazingly committed shoppers at the Prada outlet in Montevarchi, Italy, do. A modern miracle—say, a game-winning goal that curled magnetically into the net at Euro 2004—works as much magic for some as the re-enactment of medieval ones does for others. Faith is not rational. You can't argue a skeptic into belief or force anyone onto the pilgrim's path.

In Chaucer's Canterbury Tales, the Prioress wears a brooch inscribed Amor vincit omnia (Love conquers all). This is true, not least, of pilgrimage. The love that drives it springs from faith, from mockery-proof loyalty, from unwavering belief in the transcendent power of a religion or an idea or even a beautiful game. The pilgrim is no ordinary traveler. His map is in the heart.