Perez says she first felt singled out because of her faith in 1969. But then a married woman with a young son, her family still attended weekly Mass. At their church, soldiers entered, destroyed all the religious statues and burned all the sacred books.

At her son's school the administration singled him out and "made him announce that he was Catholic from a Catholic family," she says.

Perhaps the most terrifying moment -- one that instilled in Perez the desire to leave her homeland -- came one Sunday as the family was leaving Mass. Perez explains that her husband was a professor who continued to practice his faith although it was strongly discouraged by the administration. As the family was walking out of Church, one of his students was marching with a group of young soldiers.

"Angel, my husband, just froze," she says. "Then the boy walked up to him and whispered, 'Don't worry professor, I'm one of you.' We realized we couldn't keep living in fear like that."

According to Mario Paredes, presidential liaison to Catholic Ministries for the American Bible Society, the Cuban government also began "altering the calendar of the country." Christmas was banned. Easter was removed from the calendar.

"On Sundays, the government would create all sorts of activities to dissuade people from going to church." he explains.

Throughout the 1960s and 1970s, "the Church in Cuba was essentially closed," Paredes says, adding that the Papal Nuncio tried to establish relations with the Archdiocese of Havana, but the Castro regime blocked all communication.

"The country was reduced to a small number of priests -- all Cuban born -- that had to minister to the entire island," he continues. Archdiocese of Havana only recorded 7,000 baptisms. In a country that was once almost entirely Catholic, the Church was in trouble.

According to Cardinal O'Malley, when he first travelled to Cuba in 1980, he estimates that less than 1 percent of the population were practicing Catholics.

Things began to change in 1981 when a new archbishop was appointed in Havana. Then-Archbishop Jaime Ortega "was a real turning point," according to Paredes.

"With his charisma, and his willingness to speak to the outside world, we began to see what was going on in the Church in Cuba," Paredes adds.

In 1986, with the help of Cardinal Ortega, Cardinal Terence Cook, then-archbishop of New York travelled to Havana and met with Castro. At the time, Mario Paredes was director of operations for the United States Conference of Catholic Bishops (USCCB), so he traveled with Cardinal Cook to that meeting in Havana.

"In that encounter, a lot of things were said," Paredes recalls.

Ultimately, Cardinal Cook was able to negotiate the release of over 800 political prisoners. He also was granted permission for priests to visit prisoners in jail. And, perhaps most importantly, he opened the way for Havana to host Pope John Paul II.

By the 1990s, it was no longer illegal to be Catholic and a member of the Communist party. Castro, who had often described Cuba as an "atheist nation," now began referring to it as a "secular nation." In 1991, the Archdiocese of Havana reported 33,569 baptisms -- a six-fold increase from the 1971 statistic.

It seemed things were looking up for the Church in Cuba.

Then history stopped all progress in its tracks. The Soviet Union collapsed. The Berlin Wall was toppled. Communist regimes lost its power in most of Europe.

"Fidel was very upset," Paredes recalls. "He accused bishops of conspiring against his power. There was a complete breakdown of communication."

It wasn't until 1998 that Pope John Paul II would be allowed to enter the island nation.

Calling it a "watershed moment," Cardinal O'Malley believes "that visit saved the Church in Cuba."

"It really changed the landscape," he says.

That following year, Christmas was allowed to be celebrated once again.

Things would continue to change. In 2008, an aging Fidel Castro stepped down as president of Cuba, ceding his power to his younger brother, Raul.

"Fidel was very dogmatic," Paredes explains. "Raul is very pragmatic."

Seeing his nation in financial distress, and acknowledging the needs of the Cuban people, Raul Castro began to allow groups such as Caritas Cubana to minister to the Cuban people.

"Raul has been very interested in forming a relationship with the Catholic Church," Paredes says, adding quickly that "it is not an official relationship. He looks to the other side and allows Caritas to establish centers of continuing education, centers for children with disabilities and other such entities to exist."

"Private entities do not exist in Cuba, yet the Church is allowed to run these without any problem," he adds.

In 2010, a new seminary was erected in Cuba -- the first Catholic building constructed since the Revolution in 1959 -- with President Raul Castro in attendance at the inauguration ceremony.

Two years later, another pontiff visited the island. Pope Benedict XVI arrived amid throngs of people, waving papal flags, publicly declaring their faith.

Like his predecessor, Pope Benedict celebrated Mass at Revolution Square. He also visited Santiago de Cuba, the place where the statue of the patroness of Cuba, Our Lady of Charity, resides.

Following Pope Benedict's visit, the Cuban people were allowed to celebrate Holy Week -- even having Good Friday declared a national day off from work.

According to Paredes, following Pope Benedict's visit to Cuba, "the Church began to be seen not as a counter-revolutionary or anti-patriotic entity, but as an asset."

Although the Church has certainly grown in Cuba -- now more than 60 percent of the population are baptized Catholics -- there is still much work to be done, according to Paredes.

"Each pope has helped to make the revolution more flexible, more tolerant," he says, adding that there are still many things to be done.

"The Church is still not allowed to enter the field of education -- no high school, or elementary or university," he says. "They also have no access to mass media of any kind."

Yet incredible progress has been made. In the last few years, the government has begun to give the Church properties that were confiscated a half-century ago. To date, more than 120 buildings, most in disrepair, have been given back to the dioceses of Cuba.

And now, after Pope Francis' visit to Cuba in September 2015, Cubans are highly optimistic about their future.

Sitting in Old Havana, Vivian, a 43-year-old tour guide in Havana, who was not comfortable giving her last name, sees Pope Francis's visit as a real "turning point" for Cuba.

The fear they once lived in has been lifted. The paranoia that had been instilled in the people has dissipated. Continuing education in fields such as business, computers and finance are being offered in many parishes. The oppression once felt by the masses has been changed into promise.

"We can feel it in the air -- there's a hope, an electricity. You can see it when you look at people. We are hopeful. We know that things are going to get better," Vivian said.