Pope Francis waves to reporters Saturday at Rome's Fiumicino International Airport as he boards his flight to La Habana, Cuba, where he will start a 10-day trip, which includes stops in Washington, D.C., New York and Philadelphia.

HAVANA — Pope Francis begins a 10-day trip to Cuba and the United States on Saturday, embarking on his first trip to the onetime Cold War foes after helping to nudge forward their historic rapprochement. He will be offering a show of solidarity with Cubans and making clear that Hispanics in the United States are the bedrock of the American church.

The visit boasts several firsts for history’s first Latin American pope: Francis will become the first pope to address the U.S. Congress and he will also proclaim the first saint on U.S. soil by canonizing the controversial missionary, Junipero Serra.

Francis though will also be following in the footsteps of his predecessors, becoming the third pontiff to visit Cuba in the past 17 years — a remarkable record for any country much less one with such a tiny Catholic community.

And he will join three of his predecessors in grabbing the world stage at the United Nations to press his agenda on migration, the environment and religious persecution while more than 100 world leaders listen.

It’s largely unknown territory for the 78-year-old Argentine Jesuit, who has never visited either country and confessed the United States was so foreign to him he would spend the summer reading up on it. His popularity ratings are high in the U.S., but he also has gained detractors, particularly among conservatives over his critiques of the excesses of capitalism.

That has endeared him to Cuban President Raul Castro, who vowed earlier this year that if Francis kept it up, he would return to the Catholic Church.

But Francis has also been on record criticizing Cuba’s socialist — and atheist — revolution as denying individuals their “transcendent dignity.”

Pope Francis departed from Rome on a special Alitalia flight Saturday morning. The visit begins in Havana, where he will be greeted as something of a hero to Cubans who rightly credit him with having helped restore diplomatic relations between the United States and Cuba.

Francis issued a personal appeal to Presidents Barack Obama and Raul Castro last year to end 50 years of animosity, and later hosted the Cuban and U.S. delegations to finalize the deal.