13 There is the moving procession of the lowly, the sick, and the afflicted. There is the impressive pilgrimage of thousands of the faithful from a particular diocese or country. There is the quiet visit of a troubled soul seeking truth. "No one," We once said, "has ever seen such a procession of suffering in one spot on earth, never such radiance of peace, serenity, and joy!"
Source: Le Pelerinage de Lourdes (Vatican.va)