An unusual trio is in Rome this week. They're trying to convince Pope Francis to come to Philadelphia next year.

Philadelphia Mayor Nutter says he, Archbishop Charles Chaput and Gov. Tom Corbett are in the Vatican to work out logistics for the World Meeting of Families that will be held in the city in September 2015.

"The sheer possibility that Pope Francis might come to Philadelphia could obviously enhance the World Meeting of Families event," Nutter said. "It will be a spectacular event in any manner, there are just a lot of details."

Nutter says he doesn't expect the Pope to commit to the event at this point.

"It's unreasonable to expect that 18 months or so in advance that someone like Pope Francis is going to say they are going to any place in particular," he said. "President Obama doesn't make that kind of announcement either."

When asked what he will say to the Pope, Nutter said he would consult with his mother.