The world's largest gathering of young Catholics kicked off on Tuesday in Lisbon, with hundreds of thousands of pilgrims from around the globe flocking to the Portuguese capital for the event's highlight, Pope Francis, who will arrive on Wednesday.
Pilgrims have been arriving to attend World Youth Day over the last few days and will stay in schools, gyms, fire stations and with families, with many planning to sleep in the open before the closing Mass on the riverside Parque Tejo on Aug 6.
The cross-cultural festival, which actually runs for nearly a week, is held every two to three years and was initiated by the late Pope John Paul.
The celebrations will take place against the backdrop of a sexual abuse scandal in the Portuguese Church, in which at least 4,815 were found to have been abused, largely by priests, over the past 70 years. Francis is expected to meet privately with abuse victims.
There have also been separate concerns over the cost of hosting the event on one of Western Europe's poorest nations.
At the Lisbon civil parish of Olivais, volunteers welcomed pilgrims carrying suitcases and sleeping bags on Tuesday near a school that is hosting them.
Emilie Bartoschek, a 27-year-old from Germany, arrived with a big group to attend her third WYD.
"It's so important to see the beauty of people and what it means to believe and love... to be connected," said Bartoschek, who was looking forward to listening to Francis.
Huge stages have been set up, with big screens, and a brand new venue was created for the event. The opening Mass will be celebrated at the central park and garden, Parque Eduardo VII.
"It means an enormous amount to me that this is happening [and] that I can be with the community," said 25-year-old Polish pilgrim Milosz Buddy.
Francis, 86, is making his first trip since having intestinal surgery in June and uses a wheelchair and cane. He will celebrate several Masses and attend events with young people, politicians and diplomats.