Pope Leo honoured Spain’s centuries-old tradition of religious devotion on Sunday as a “school of faith” for today, as he presided over a Mass before more than a million people that highlighted one of the most iconic expressions of Spanish popular piety: a procession over flower-petal carpets. The crowd cheered and shouted “This is the youth of the pope!” as Leo arrived for the Mass at a central Madrid plaza. He looped around the plaza and surrounding streets in his Popemobile before a crowd...