As hundreds of thousands of pilgrims embark on their journey to Portugal this August, I am reminded fondly of so many other World Youth Day events of the past.

My first World Youth Day, and probably the most significant for us in the United States, was held in Denver in 1993, exactly 30 years ago. But I had been tangentially involved with the earlier events in Santiago de Compostela, Spain, (1989); and Czestochowa, Poland, (1991), in my youth outreach work at Franciscan University of Steubenville. I and others were taking notice as the new phenomenon of World Youth Day exploded in the Catholic Church.

When I heard that the 1993 event was going to be in the U.S., I started planning immediately to organize a trip on behalf of Franciscan. We took 800 teens and young adults to Denver, and it was one of the most memorable experiences of my life. I saw the impact and long-term fruits of the event and would eventually plan and lead three more trips: Paris in 1997, Rome in 2000 and Madrid in 2011.

Over the years, I have seen both the challenges and the fruits of the World Youth Day experience. In Madrid in 2011, a priest from Phoenix offered Mass for a group of us; during his homily, he said: “In the crucible of suffering and difficulty is when we really grow.”

We had all experienced significant hardship throughout the entire trip that year, and his parting words reminded us that God often accomplishes what he is desiring to do in us through hardship and difficulty. This was the last event that I attended personally, and these words captured well all four of my World Youth Day experiences.

There is something about a World Youth Day pilgrimage experience that challenges us to an intense form of growth and purification.

In 1993 in Denver, many participants suffered heat exhaustion at the final event. Young people were leaving in ambulances all during the closing Mass; and by the time it was over, our group was missing 35 teens. I’ll never forget going to the main medical tent to get information and being given only the names and addresses of four hospitals in the area — the overwhelmed medical personnel had stopped tracking who was sent where. It took us more than 12 hours to track down the missing teens, which delayed our cross-country bus ride back to Steubenville. By the time we finally got back home, I had not slept for almost three full days, and we all knew what the priest meant by “the crucible of suffering and difficulty.”

I experienced suffering and difficulty at every one of the four trips I attended, and memories like these are commonplace among World Youth Day attendees. To dwell too long on the hardships, though, would be to miss the whole point: “That’s when we really grow.”

This supernatural growth has certainly been true for me and in the lives of so many other World Youth Day pilgrims I’ve met.

My friend Aaron, who attended World Youth Day in Denver as a 15-year-old, said, “At that time I was running away from God, habitually in mortal sin and grasping ravenously at anything that would bring any momentary reprieve from the void I felt inside. That day, something was unearthed in the deepest parts of me. When John Paul II arrived at Cherry Creek Park, I felt waves of the Holy Spirit. … As he spoke, I felt exposed and seen by God. He exposed my sin; he knew my shame and yet he loved me with a love that was so intense and personal.”

“That experience,” Aaron said, “awoke in me the mission that God created me for and gave me an unrelenting hunger in my heart for his love and presence in my life.”

Another fellow pilgrim, Natalia, recalled a homily she heard at another World Day Youth Mass: “The priest shared that Jesus desires to be our best friend,” she said. “He invited anyone who wanted to respond to that call and be best friends with Jesus to come down. From the top auditorium seats, I walked down toward the altar to accept his invitation. That invitation changed my life.”

“I went home in love with Jesus,” she said. “I invited him into all of my decisions — where was I going to go to college? Which friends should I hang out with? How should I treat my sisters? In fact, meeting Jesus as my best friend changed me so much that my two younger sisters cite my conversion as a catalyst for their own relationships with Jesus.”

“I used to think God was a distant god who ruled the earth but was far removed from my personal experience,” Natalia said. “My encounter with Jesus as Friend opened me up to the personal nature of God.”

Ben, who attended World Youth Day in Rome in 2000, was struck by his experience of the universality of the Church. “I remember standing in this sea of people in St. Peter’s Square in Rome,” he said, “surrounded by over a million other young Catholics, and thinking, ‘This is the Body of Christ!’ We were from different countries, we looked different, we spoke different languages, and we had different hopes and desires, but we were all together because we loved Jesus.”

He said Pope John Paul II’s closing homily “gave me permission to expect God to do great things in and with me — to trust that anything was possible with him, to believe in the unbelievable, and to wait with expectant faith to see him act.

“I am blessed to get to share that same ‘expectant’ reality with my children every day, to help them grow in their trust of our good Father — and he never disappoints.”

World Youth Day holds a special significance for Kate, who helped lead a Colorado youth group to Toronto in 2002. At the opening event, she said, “We found our way through the maze of youth from all over the world till we saw a massive Texas flag waving a short distance ahead of us. Past the flag in the background was the stage where Pope John Paul II would soon greet us with the radiant love and affection of God the Father. But underneath the flag was a handsome college friend who shouted my name in the midst of a swirl of excitement and about 500,000 other pilgrims.

“That same Texan would later say my name again in a swirl of grace which would begin our life together in holy matrimony as we both said, ‘I do.’ One pilgrimage led to the other. Now, 18 years of marriage and eight beautiful children later, I treasure that providential encounter in Toronto as one of the marvels the Lord has done in my life, and I am forever grateful.”