As America prepares to celebrate its 250th birthday next month, Philadelphia will once again become the center of the national story. The city where independence was declared and the Constitution was debated is already buzzing, preparing events and commemorations intended to remind people who we are and where we came from. The story of the United States is not merely a story of representative government or constitutional design. It is the story of religious liberty, perhaps the most distinctive and enduring contribution the U.S. has made to the world.I was reminded of that fact while walking through Philadelphia recently. Like most visitors, we visited the familiar pilgrimage to sites associated with the Founding Fathers. I visited Christ Church Burial Ground, where Benjamin Franklin rests. I toured Mikveh Israel, often called the Synagogue of the American Revolution and the oldest continuously operating Jewish congregation in the U.S. Standing in those spaces, separated by only a short walk but representing traditions that were marginalized, persecuted, or excluded elsewhere in the world, it became impossible not to notice that the physical map of Philadelphia tells a deeper story than most history textbooks ever could.