By Eric Marrapodi and Miguel Marquez, CNN

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Rio de Janeiro (CNN) – For the first time in the history of the Catholic Church, a Latin-American pope will touch down on his own continent on Monday.

Pope Francis, the 76-year-old Argentine, begins his first apostolic visit Monday in Brazil, home to the world’s largest Catholic population. The pope will be participating in World Youth Day, a weeklong celebration aimed at revitalizing young Catholics, and the church, here and around the world.

Organizers said 400,000 pilgrims from around the world had registered, though the crowds are expected to be much larger as people try to catch a glimpse of the pontiff known as the “people’s pope.” Many of the events with the pope will be open to the public and not just the pilgrims.

Francis arrives in Brazil at a touchy time. Social unrest has been brewing here in Rio and across the country for weeks. Protesters have rallied, sometimes violently, against a lack of government services and problems with public transportation and corruption.

The Rev. Marcio Queiroz, a World Youth Day spokesman in Brazil, said there are some security concerns but that the protesters also represent "a face of God."

World Youth Day organizers say the final tab for the trip could cost as much as 350 million reals ($156 million) with pilgrims picking up 70 percent of the tab. More than 20,000 jobs related to the event will be created, according to the organizers, who estimated that the festivities could add more than half a billion reals ($222 million in U.S. dollars) to Brazilian coffers.

A wide variety of protesters will try to use the pope’s visit to draw attention to their causes over the course of the week. A gay rights group is staging a kiss-in along the route where Francis is scheduled to drive through the city in an open-topped "popemobile."

The pope’s choice to use a popemobile without bulletproof glass has caused security concerns. Brazil’s Gen. Jose Abreu, who is overseeing the papal visit, said “the bulletproofing would lessen our worries.” But, he conceded, “it’s a personal choice and we’ll respect it, but it’s not remotely pleasant for security forces.”

The Brazilian government has deployed thousands of security forces to protect the pontiff.

WATCH: Brazil prepares for Pope Francis' arrival

The pope carried his own luggage as he boarded the papal plane in Rome bound for Rio De Janeiro.

Aboard the plane to Rio, the pope spoke briefly with reporters and did not take questions. "The global crisis has brought nothing good to young people. I saw the data on youth unemployed last week. We run the risk of having a generation without work," Francis said. He told reporters he hoped to engage in dialogue on the issue during his trip.

As the sun rose over Copacabana Beach on Monday, workers furiously hammered, sawed, and painted the main stage ahead of the pope’s arrival. The massive stage is being built 100 yards away from the crashing waves. Giant screens and speakers line the beach for more than a mile from the main stage.

“We've been fund-raising for a year now and it's just amazing. God's work has brought us here, and it's such an amazing feeling,” said Sarah Butler, a Catholic pilgrim from Austin, Texas.

On Tuesday the stage will play host to the welcoming Mass for pilgrims from around the world. The pope will greet the pilgrims Thursday on the beach.

World Youth Day takes place every two years and was planned long before the pope’s election in March. Shortly after his election, Francis confirmed he would be attending the event, and then added many stops to the papal agenda that had been prepared for his predecessor, Pope Benedict XVI.

While in Brazil, the pope will visit one of the world’s biggest shrines to the Virgin Mary, who is revered here; visit a hospital for recovering drug addicts; hear confessions from juvenile prisoners; and visit a slum known as a favela.

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Brazil is home to an estimated 123 million Catholics, but that population has dropped significantly in the last few decades. In the 1970s, census data showed the country was over 90% Catholic. In 2010 Catholics made up 65% of the population, as the numbers of evangelical Protestants and religiously unaffiliated Brazilians grew by large margins.

Datafolha, one of Brazil's leading research companies, put the percentage of Catholics in Brazil at 57% in a new survey on religious affiliation released on Sunday.

CNN's Barbara Arvanitidis and CNN contributor John Allen contributed to this report.