Mayor Bill de Blasio is Vatican-bound. 

The mayor is traveling to his self-proclaimed “ancestral homeland” to give a talk on climate change at Pope Francis’ conference, called “Modern Slavery and Climate Change: The Commitment of the Cities.”  

De Blasio is scheduled to give remarks at the New Synod Hall at the Pontifical Academy of Sciences on Tuesday morning. He will attend private meetings with some of the 65 world mayors set to attend the conference, and wrap up the day with an official dinner organized by the Vatican. 

The mayor is expected to give a 15-minute keynote address at the Symposium on Cities and Sustainable Development on Wednesday morning, and return to the Big Apple on Wednesday evening.