The man walking across the Plaza de Obradoiro is dressed in an outfit quite unlike anything else my wife and I have ever seen before. His broad-brimmed felt hat, which is turned up at the front, is decorated with a bright scallop shell. He is holding onto an eight-foot-long stave. The stave also has a scallop shell attached—plus a gourd tied to it at the top. He is wearing extraordinarily thick sandals. He is also wearing a long-hooded cloak that is decorated with three more scallop shells. We are in northern Spain, in Santiago de Compostela. Long ago, this city was a top destination in Europe, one of the most famous places in the world, considered one of the three great pilgrimage sites of Christianity, after Jerusalem and Rome. Here, says Spanish lore, Christianity’s first martyr, the Apostle St. James, was buried and later appeared to rally Christians for their …