Raul Castro Thanks Pope for US Mediation Role

Security has been heightened in Washington, D.C., for Friday's presidential inauguration, Jan. 19, 2017.

Pope Francis arrives for an audience with a group of children in the Paul VI hall at the Vatican, May 11, 2015.

Dawn breaks behind the Capitol Dome as last minute preparations continue for swearing in of Donald Trump as the 45th President of the United States, Jan. 20, 2017.

Cuban President Raul Castro waves as Pope Francis looks at him, at the end of a private audience at the Vatican, May 10, 2015.

Pope Francis exchanges gifts with Cuban President Raul Castro during a private audience at the Vatican, May 10, 2015.

Pope Francis meets Cuban President Raul Castro during a private audience at the Vatican, May 10, 2015.