Pope Francis visits the 9/11 Museum, Friday, Sept. 25, 2015 in New York. (Susan Watts/New York Daily News via AP, Pool)
Former New York City Mayor Michael Bloomberg is joined by Pope Francis as he views a New Testament bible fragment found in debris of the South Tower of the World Trade Center. (Carmine Galasso/The Record of Bergen County via AP, Pool)
Pope Francis, second left, reads a passage during a multi-religious service at the 9/11 Museum, Friday, Sept. 25, 2015 in New York City. (Monica Graff/Pool via AP)
Pope Francis greets Gunisha Kaur, member of Sikh community, as he arrives for an interfaith service at the Sept. 11 memorial museum in New York, Friday Sept. 25, 2015. (AP Photo/Alessandra Tarantino)
Pope Francis looks at Imam Khalid Latif, right, and Rabbi Elliot J. Cosgrove, left, shaking hands as he arrives for an interfaith service at the Sept. 11 memorial museum. (AP Photo/Alessandra Tarantino)
Pope Francis places a white rose at the South Pool of the 9/11 Memorial in downtown Manhattan, Friday, Sept. 25, 2015, in New York. (AP Photo/John Minchillo)
Pope Francis prays at the edge of the South Pool at the World Trade Center in New York, Friday, Sept. 25, 2015. Pope Francis is on a five-day trip to the United States. (AP Photo/Julio Cortez, Pool)
Pope Francis and Cardinal Timothy Dolan, left, pray at the South Pool of the 9/11 Memorial in downtown Manhattan, Friday, Sept. 25, 2015, in New York. (AP Photo/John Minchillo)
Pope Francis waves as he arrives at the South Pool of the 9/11 Memorial in downtown Manhattan, Friday, Sept. 25, 2015, in New York. (AP Photo/John Minchillo)
Pope Francis visited the 9/11 Memorial and Museum in New York on Friday, where he spent time praying before participating in a multi-religious ceremony and touring parts of the museum.