FILE - In this April 20, 2008 file photo, Pope Benedict XVI acknowledges guests during a ceremony for victims' families, survivors, and first responders from the World Trade Center attacks during a visit to ground zero in New York. In 1965 Pope Paul VI made the first papal visit to the United States. Fifty years later, Pope Francis is scheduled to attend the World Meeting of Families in Philadelphia in September 2015. (AP Photo/Kathy Willens, Pool, File)