Pope Francis arrives in the U.S.

Pope Francis arrives in the U.S.

WASHINGTON, D.C. (WCSC/CBS News) - The plane carrying Pope Francis from Cuba landed just before 4 p.m. Tuesday, as the pontiff makes his first visit as leader of the world's Catholics.

President Obama, first lady Michelle Obama, Vice President Joe Biden and his wife, Dr. Jill Biden, were on the tarmac to greet the pontiff at Joint Base Andrews in Washington, D.C. A motorcade departed shortly before 4:30 p.m. bound for the White House.

Security teams in the nation's capital spent the day making final preparations for the Pope's arrival.

The Pope's arrival begins a six-day tour of the U.S., which includes several high-profile events in three of the nation's largest cities.

While in Washington D.C., Pope Francis will be the first to address Congress.

The Pope plans to talk about immigration, climate change and criminal justice reform during his visit. He will also travel to New York to visit the United Nations and Philadelphia where he will meet with religious leaders.

Francis will be the fourth Pope in history to visit the United States. The first was Pope Paul VI in 1965. According to Georgetown University, there were 46.3 million Catholics in the U.S. in 1965; by 2014, that number had grown to more than 66 million.

A new CNN/ORC poll shows nearly half of Americans in general and 78 percent of those who identify as Catholic say they are looking forward to the Pope's visit.

The security plan has thousands of federal, state and local law enforcement assigned to watch over the pontiff as well as the millions expected to gather to see him.

Catholics in the Lowcountry say they are excited for the visit of the pontiff who has been nicknamed "the people's Pope."

The greatest concern, security experts say, is an attack by a "lone wolf."

"No one can say with 100 percent certainty that you can stop everything," Philadelphia Police Commissioner Charles Ramsey said.

Earlier Tuesday, Francis celebrated a final mass in Santiago during which he called Catholicism the foundation of Cuban identity and called for a "revolution of tenderness" as Cubans reconsider their heritage.

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