Italy, which surrounds Vatican City, the spiritual home to the world's 1.1 billion Catholics, boasts more than 30,000 churches and sanctuaries, according to the country's Ministry of Culture. That's more churches per capita than any other major country. And according to United Nations' World Tourism Organization statistics, seven of the world's 10 most visited Christian sanctuaries are in Italy.
Official figures are hard to come by because visitors to Italy are not required to indicate whether or not their vacation is religious in nature.
Italy's Ministry of Tourism reports that overall tourism over the first two months of the year is down by a fifth over the same period last year.
However, tour operators and travel agents say that the number of religious tourists in Italy hasn't changed much.
"It's one of the only areas where things haven't slowed down much," said Michele Patano, the director of Aurea, a 6-year-old trade fair for agencies that market religious tours. "Religious pilgrims still want to have the same experiences."
Patano said attendance at the Aurea fair this November is expected to easily surpass last year's record levels. Patano estimates that around 10% of Italy's tourism industry is tied to religious themes.
The high point for religious tourism in Rome is Easter, which takes place on Sunday. The Vatican says that if the weather is good, attendance at the Easter Mass in St. Peter's Square could surpass 100,000 people.
"Every three or four years I come to Rome for Easter with a church group," said Ramona Casey, a 63-year-old retired nurse from Philadelphia, who came with six other members of her church.
"Money is tighter now, but not so tight we couldn't make the trip. It's a priority for us," Casey said.
Scott Chord, a 33-year-old lawyer from Scottsdale, Ariz., made his first trip to Rome with his wife and their young son. He said that they have been visiting about two churches per day along with other cultural landmarks and that they plan to attend Easter Mass at the Vatican.
"We just promised ourselves we would make the trip," he said.
The Rev. Gregory Apparcel says people tend to save up over long periods for religious-themed trips, making them less susceptible to dramatic changes in the economy.
Apparcel, of Temple City, Calif., is the rector at Santa Susanna, one of approximately two dozen English-language churches in Rome.
"There's an old cliché that says that when times are tough, people spend more time in the movies and at church," Apparcel said.
Matteo Marzotto, president of the Italian government's tourism board, said the reason that crowds keep coming despite the recession is that that religious tourists tend to be wealthier than non-religious tourists.
Even so, he does not see these tourists making a dent in Italy's economy, one of the weakest in the European Union.
"Religious tourists probably tend to spend less money than average," he said. "After all, churches don't cost anything to visit, and my guess is that for the most part they are less likely to spend large sums on luxuries."