Pope Francis prays at the grave site of shepherd children Jacinta and Francisco Marto at the Sanctuary of Our Lady of Fatima, Saturday, Friday, May 13, 2017, in Fatima, Portugal. Pope Francis urged Catholics on Friday to "tear down all walls" and spread peace as he traveled to this Portuguese shrine town to canonize two poor, illiterate shepherd children whose visions of the Virgin Mary 100 years ago marked one of the most important events of the 20th-century Catholic Church. (Paulo Cunha/Pool Photo via AP)