Pope Francis visits the U.S.

An unidentified child, who was carried out from the crowd to meet Pope Francis, reaches out to touch the pontiff’s face during a parade on his way to celebrate Sunday Mass on the Benjamin Franklin Parkway in Philadelphia.

Pope Francis waves on the way to an open-air Mass at the Benjamin Franklin Parkway in Philadelphia on Sunday.

Pope Francis passes banners marking his visit to Philadelphia on his way to an open-air Mass at the Benjamin Franklin Parkway.

Pope Francis greets inmates at Curran-Fromhold Correctional Facility on Sept. 27, 2015, in Philadelphia.

Pope Francis speaks to international bishops at Saint Charles Borromeo Seminary on Sept. 27 in Wynnewood, Pa.

Sisters with Handmaids of the Heart of Jesus in Minnesota cheer as Pope Francis passes on Benjamin Franklin Parkway in Philadelphia.

Pope Francis takes the stage at the Festival of Families in Philadelphia.

Spectators watch for Pope Francis along Benjamin Franklin Parkway in Philadelphia.

Pope Francis waves to the crowd in Philadelphia.

A large crowd lines Pope Francis’ route outside Independence Mall.

Sister Mary Celeste, left, and Sister Mary Rose of Nashville wait for Pope Francis to arrive at the World Festival of Families on Sept. 26, 2015, in Philadelphia.

A crowd gathered outside listens to Pope Francis’ morning Mass at Cathedral Basilica of Saints Peter and Paul in Philadelphia.

Nuns wait behind a security barrier on Independence Mall in Philadelphia awaiting Pope Francis’ arrival on Sept. 26, 2015.

Pope Francis blesses a child during Mass at the Cathedral Basilica of Saints Peter and Paul in Philadelphia on Sept. 26, 2015.

Pope Francis and Archbishop Charles Chaput, right, at the conclusion of Mass at the Cathedral Basilica of Saints Peter and Paul in Philadelphia on Sept. 26, 2015.

Crowds looking to catch a glimpse of Pope Francis gather along Benjamin Franklin Parkway in Philadelphia, across the street from the Cathedral Basilica of Saints Peter and Paul, where the pope had just celebrated Mass, on Sept. 26, 2015.

David Martinez, right, of Conyers, Ga., waits for Pope Francis along Benjamin Franklin Parkway early Sept. 26, 2015, in Philadelphia

Nuns from the Monastery of the Precious Blood in Brooklyn, N.Y., wave as Pope Francis prepares to board his plane at John F. Kennedy International Airport for Philadelphia on Saturday.

Pope Francis, left, celebrates Mass at Madison Square Garden.

The chorus is seen during Mass led by Pope Francis at Madison Square Garden.

A crowd gathers outside Madison Square Garden, where Pope Francis celebrated Mass.

Thousands of people lined the route through Central Park in New York cheering as Pope Francis passed by.

Pope Francis looks on during a multi-religious prayer for peace at the 9/11 Memorial and Museum in New York.

Pope Francis places a white rose at the south pool of the 9/11 Memorial in downtown Manhattan.

Pope Francis visited Ground Zero following his address at the United Nations in New York.

Pope Francis takes part in a multi-religious service for the victims of 9/11 at the memorial in New York.

Pope Francis addresses the General Assembly of the United Nations.

Pope Francis addresses the General Assembly of the United Nations.

Pope Francis arrives to address the General Assembly of the United Nations.

U.N. staffers take photos as Pope Francis arrives to greet them Friday at U.N. headquarters in New York.

Pope Francis is applauded after addressing the United Nations General Assembly in New York.

One U.N. staffer attempts to take a selfie with Pope Francis in the background Friday at United Nations headquarters in New York.

Pope Francis emerges from St. Patrick’s Cathedral.

A crowd gathers for Pope Francis’ arrival at St. Patrick’s Cathedral.

Cardinals wave goodbye to Pope Francis after an evening prayer service at St. Patrick’s Cathedral in New York.

A crowd gathers along Fifth Avenue in New York before the pope’s arrival at St. Patrick’s Cathedral.

Pope Francis makes his way through St. Patrick’s Cathedral after the prayer service. i

Pope Francis arrives at St. Patrick’s Cathedral in Manhattan to an enthusiastic crowd.

Pope Francis arrives at St. Patrick’s Cathedral in Manhattan to an enthusiastic crowd.

Pope Francis greets the crowd upon his arrival at St. Patrick’s Cathedral.

Nuns are checked by security personel before entering St. Patrick’s Cathedral, where Pope Francis will appear in New York City on Sept. 24, 2015.

Pope Francis, accompanied by members of Congress, waves to the crowd from the Speakers Balcony on Capitol Hill in Washington on Sept. 24, 2015, after addressing a joint meeting of Congress.

In Statuary Hall at the U.S. Capitol, Pope Francis pauses in front of a sculpture of Spanish-born Junipero Serra, the Franciscan friar known for starting missions in California.

Pope Francis addresses a joint meeting of Congress on Sept. 24.

Pope Francis addresses a joint meeting of Congress, making history as the first pontiff to do so.

Crowds watch Pope Francis on a large-screen television from the West Front of the Capitol on Sept. 24.

Pope Francis conducts Mass outside the Basilica of the National Shrine of the Immaculate Conception in Washington.

Pope Francis greets well-wishers as he returns for the night to the Vatican’s diplomatic mission in Washington.

Pope Francis arrives in the popemobile for the Canonization Mass of Blessed Junipero Serra on Sept. 23, 2015 at the Basilica of the National Shrine of the Immaculate Conception in Washington, D.C.  (Steve Helber / AP)

Pope Francis lays flowers on a side alter with Msgr. W. Ronald Jameson, left, and Cardinal Donald Wuerl, archbisop of Washington, at the Midday Prayer of the Divine with more than 300 U.S. bishops at the Cathedral of St. Matthew the Apostle on Sept. 23.

Pope Francis leaves St. Matthews Cathedral in his Fiat 500 after a midday prayer service in Washington on Sept. 23 as bishops applaud.

Pope Francis places his hand on the forehead of a young woman in a wheelchair as he arrives at the Apostolic Nunciature, the Vatican’s diplomatic mission in Washington, on Sept. 23.

President Barack Obama talks with Pope Francis in the Oval Office of the White House.

President Obama and First Lady Michelle Obama wave from the balcony with Pope Francis in an arrival ceremony at the White House.

Pope Francis and President Obama review the U.S. Army’s Old Guard Fife and Drum Corps during the pope’s arrival ceremony at the White House.

Pope Francis takes a photo with children whose parents work at the Lithuanian Embassy, outside the Apostolic Nunciature to the United States, in Washington.

President Obama hosts Pope Francis at the White House for the first time Wednesday, warmly welcoming the Catholic pontiff seen as both a moral authority and potent political ally.

Pope Francis arrives for the Midday Prayer of the Divine with more than 300 U.S. bishops at the Cathedral of St. Matthew the Apostle on Sept. 23 in Washington.

Pope Francis receives a kiss outside the Apostolic Nunciature to the United States in Washington.

People listen as Pope Francis speaks during an arrival ceremony at the White House.

President Obama and Pope Francis stand during a state arrival ceremony on the South Lawn of the White House.

President Obama welcomes Pope Francis during a state arrival ceremony Sept. 23 on the South Lawn of the White House.

Pope Francis waves from his car after arriving at Joint Base Andrews in Maryland on Tuesday.

Pope Francis, left, greets children as he is escorted by President Obama, center, and First Lady Michelle Obama after arriving at Joint Base Andrews in Maryland on Tuesday.

Supporters cheer for Pope Francis after he arrived from Cuba at Joint Base Andrews in Maryland on Tuesday.

President Obama and First Lady Michelle Obama greet Pope Francis at Joint Base Andrews in Maryland on Tuesday.

Pope Francis arrives Tuesday at Joint Base Andrews in Maryland for the start of a six-day visit to the United States.

The plane carrying Pope Francis arrives at Joint Base Andrews in Maryland on Tuesday.