World Youth Day (WYD) is an event for young people organized every three years by the Catholic Church.
World Youth Day was initiated by Pope John Paul II in 1985. For the first celebration of WYD in 1986, bishops all over the world were invited to schedule an annual youth event to be held every Palm Sunday in their dioceses. It is celebrated at the diocesan level annually, and at the international level every two to three years at different locations.
In 1993 WYD was celebrated in Denver, United States, theme: "I came that they might have life, and have it to the full." – Jn 10:10
The 1995 World Youth Day closing Mass in the Philippines set a world record for the largest number of people gathered for a single religious event (with 5 million attendees)— a record surpassed when 6 million attended a Mass celebrated by Pope Francis in the Philippines 20 years later in 2015.
The World Youth Day 2016, will be held 25–31 July 2016 in Krakow, Poland
The youth continue to answer the invitation of the Holy Father in staggering numbers and carry home the message received there to be Christ’s light to the world. While these events are organized by the clergy and laity of the Catholic Church, youth of all faiths are invited to attend and encounter Christ, making this gathering truly universal.
The World Youth Day in 2019, will be held 22 - 27 January in Panama City, Panama. Theme: I am the servant of the Lord. May it be done to me according to your word (Lk 1:38)
Source: worldyouthday.com | wikipedia.org | vatican.va
In 2022 World Youth Day in USA falls on January 22.