In the Middle Ages the Camino de Santiago (the Way of St. James) had been described as the busiest trunk road in Christendom, with half a million pilgrims a year. The goal was to achieve redemption by the hard slog of walking — and by standing at journey’s end in the presence of the relics of one of Jesus’ apostles. In 2022, 45 percent of pilgrims still list their reason for walking as religious, an impressive number in a post-Christian era.