World Youth Day (WYD) is an event for young people organized by the Catholic Church that was initiated by Pope John Paul II in 1985. Its concept has been influenced by the Light-Life Movement that has existed in Poland since the 1960s, where during summer camps Catholic young adults over 13 days of camp celebrated a "day of community". For the first celebration of WYD in 1986, bishops were invited to schedule an annual youth event to be held every Palm Sunday in their dioceses. Nicknamed "The Catholic Woodstock", it is celebrated at the diocesan level annually—in most places on Palm Sunday from 1986 to 2020, and from 2021 on Christ the King Sunday—and at the international level every two to three years at different locations. 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. This record was surpassed when 6 million attended a Mass celebrated by Pope Francis—again in the Philippines—20 years later in 2015. World Youth Day is commonly celebrated in a way similar to many events. The most emphasized and well known traditional theme is the unity and presence of numerous cultures. Flags and other national declarations are displayed among mainly young people to show their attendance at the events and proclaim their own themes of Catholicism. Such is usually done through chants and singing of other national songs involving a Catholic theme. Over the course of the major events taking place, national objects are traded between pilgrims. Flags, shirts, crosses, and other Catholic icons are carried amongst pilgrims which are later traded as souvenirs to other people from different countries. A unity of acceptance among people is also common, with all cultures coming together to appreciate one another. Other widely recognized traditions include the Pope's public appearance, commencing with his arrival around the city in the "Popemobile" and then with his final Mass held at the event.