PHILADELPHIA (AP) — Philadelphia's mayor says it's a "joyous day." Michael Nutter says the upcoming visit by Pope Francis to Philadelphia will be the largest event in the city's modern history.

The pontiff confirmed today that he will make his first papal visit to the United States with the trip to Philadelphia next September for the World Meeting of Families. It's a conference held every three years in a different city to celebrate the importance of family.

The pope is also expected to visit New York and Washington, but Vatican officials aren't yet confirming those legs of the trip. It will be the first papal visit to the United States in eight years.

Vatican officials toured Philadelphia in May. And President Barack Obama has extended an invitation, as have the U.N. secretary-general and leaders of Congress.

Last week, the Vatican's envoy to the United Nations strongly hinted that Francis would visit New York to address world leaders at the General Assembly.

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