Last September, Pope Francis descended into the 9/11 Memorial Museum and presided over a multifaith prayer ceremony of great breadth and resolve. “We can and must build unity on the basis of our diversity of languages, cultures and religions,” he said. “Together we are called to say ‘no’ to every attempt to impose uniformity and ‘yes’ to a diversity accepted and reconciled.” Alongside leaders from many faith traditions, he prayed before the raw slurry wall that protects the World Trade Center site, its symbolic power never more evident than on that day. In that unforgettable moment, full of grief and hope, a secular museum became a holy temple.