In 2011, Luis Martinez, 29, traveled to Madrid, almost by accident. He said it was destiny that took him from his home in Fresnillo, Mexico, as a pilgrim to World Youth Day. Someone could not go at the last minute, and he ended up taking the spot.
James Kelliher, 27, was also there, visiting from London. He said his country can be "aggressively secular," something that challenges him to think about what he believes and ultimately landed him in Madrid among millions of young Catholics from all over the world.
Both said the pilgrimage changed their lives, so much that they are now volunteering in Rio de Janeiro, preparing for 2 million pilgrims that will arrive in the city July 23-28 for World Youth Day. In addition, Pope Francis will make his first international trip to attend the event.
Martinez arrived in Rio in January, Kelliher in February. Kelliher said he cannot get enough Guarana, one of Brazil's most popular soft drinks, while Martinez wondered how he ended up "in the only country in the world where they eat avocado with sugar and milk." He thinks it should be with salt, as served in his beloved guacamole.
About 4,500 international volunteers will contribute to World Youth Day; an additional 55,500 Brazilian volunteers are lending a hand.
Martinez works as the Spanish language volunteer coordinator, a vital role because the majority of international volunteers speak Spanish.
Kelliher works as the social media English coordinator and in May became co-author of "World Youth Day: Inspiring Generations," a book of testimonies from those who have attended past pilgrimages.
"I was so inspired by the event that I felt I had to do more things with my faith," Kelliher said. "It can be difficult being a young Catholic these days; I wanted to do something to help young people feel they weren't alone."
Martinez said people often look for happiness in places where it cannot be found. He said he has come to realize that happiness is expressed automatically among those who share the same faith.
"I am without words for the people of Rio de Janeiro," Martinez said. "When they open their doors to you, they open them all the way, not halfway."
Martinez lives with a young host couple, Leandro and Danielle Franca, in Vila Isabel, a middle-class neighborhood known for its samba. The couple is one of more than 20,000 families hosting volunteers and pilgrims.
In July, the Francas will welcome five more pilgrims into their two-bedroom apartment. Leandro Franca said opening the couple's home is an expression of their Catholic faith and at the same time a rich cultural exchange.
Martinez is learning Portuguese, and the Francas are picking up Spanish, while incorporating Martinez's guacamole into their diet.
Rio de Janeiro is one of the most expensive cities in the Western Hemisphere, and the cost of hotel rooms in the city has risen 50 percent in the past two years. Ines San Martin, a World Youth Day press officer, said the international event would not be possible without volunteers such as Martinez and Kelliher and host families such as the Francas.
"Host families are particularly important in receiving with open arms pilgrims who, for diverse reasons, travel alone to the event," San Martin said. "Being received by a family, these pilgrims feel more like part of a group than if they were to stay with already formed groups of friends."
Martinez and Kelliher have seen less of their host families as they log long hours in the office. Churches across Rio de Janeiro continue to urge members of their parishes to open their doors to pilgrims, as more homes are needed to take on the large number of youth.
Leandro Franca said while Brazilians are people of faith, he hoped World Youth Day would ignite what he called a "sleeping faith" in the people of Rio.
"We are doing all this work because World Youth Day will leave its mark on our hearts, on the people we've come to help, on the pilgrims and, above all, on the city," he said.