New York City's mayor will give a speech at the Vatican next week.
Mayor de Blasio will discuss climate change and income inequality during the address on Tuesday.
He'll be attending a conference called "Modern Slavery and Climate Change: The Commitment of The Cities."
Officials say he'll join other U.S. mayors for an audience with the pope on Tuesday.
The mayor is departing from New York City for Rome on Monday night.
He'll be leaving for home again Wednesday.
He'll be traveling with two staffers. The city is covering the cost of the trip.