Pilgrim's Progress; The world--and Europe especially--is rediscovering the power of the pilgrimage. The story of this improbable new vogue.

Byline: Christopher Dickey (With Edward Pentin on the Camino de Santiago, Barbie Nadeau in Rome, Jose D. Pacas in Mexico City and Joanna Chen in Jerusalem)

In 1986, the best-selling Brazilian author Paulo Coelho walked the ancient religious road from the French border to the Cathedral of Santiago de Compostela in northwestern Spain. In those days, he recalls with a smile, perhaps 450 people made the famous pilgrimage each year. Today, that many do it daily. Some 100,000 pilgrims registered with the Roman Catholic Church in Santiago last year, after trekking along the 764-kilometer route--and European officials believe three or four times as many completed all or part of the journey but never formally presented themselves to be counted.

This summer, the numbers are expected to be even higher. Indeed, during the peak months of July and August the sinuous tracks through the Pyrenees (where an English pilgrim died of the cold earlier this month) and the rocky trails along the hillsides of Galicia that are the Camino de Santiago--or "The Way of Saint James," as it is called in English--will at times resemble a carnival boardwalk as much as a high road to the holy. The pilgrims will come in all sizes and shapes, from every compass point on the globe. Some will walk or ride bicycles; others will go by horseback or roll along in wheelchairs. A few walk the route's entire length, others just a short portion. Whatever the measure of their ardor, all are part of a fast-growing global phenomenon, a new era of pilgrimage that is transforming the way many people worship and the way they see themselves.

Pilgrimages have been around for millennia and have always been voyages of self-discovery. Each is "a transformative journey to a sacred ...