After 12 years of serving as the 266th head of the Roman Catholic Church, Pope Francis died on April 21 at the age of 88.Francis' body will lie in state at St. Peter's Basilica in Vatican City before his burial in the Basilica of Santa Maria Maggiore in Rome on Saturday. World leaders, including President Donald Trump, French President Emmanuel Macron, and Ukrainian President Volodymyr Zelenskyy, are set to attend.A new pope will be chosen by the College of Cardinals in a papal election known as the conclave.Photos show powerful moments from the late pope's funeral proceedings. After Pope Francis' death was announced on Easter Monday, mourners assembled for an evening rosary prayer in St. Peter's Square. A rosary prayer in suffrage of Pope Francis in St. Peter's Square. Massimo Valicchia/NurPhoto via Getty Images Visitors left flowers, candles, and photos of the late pope. A memorial for Pope Francis in St. Peter's Square. Christoph Reichwein/picture alliance via Getty Images Francis lay in state in an open wooden coffin on Tuesday at Casa Santa Marta, his papal residence. Cardinals prayed at the Chapel of Santa Marta. Simone Risoluti Vatican Media via Vatican Pool/Getty Images On Wednesday, his body was transferred to St. Peter's Basilica, one of the holiest sites in the Catholic church, for three days of public viewing. Pope Francis' body was transferred to the Basilica at St. Peter's Square. Christopher Furlong/Getty Images His coffin was placed in front of the Altar of the Confession, which sits above what is believed to be the tomb of Saint Peter, one of Jesus' Twelve Apostles. Pope Francis' coffin at St. Peter's Basilica. Ernesto Ruscio/Getty Images After leading the procession to the Basilica, the Cardinals conducted a service featuring liturgical readings and hymns. Cardinals paid their respects to Pope Francis inside St. Peter's Basilica. ALESSANDRO DI MEO/POOL/AFP via Getty Images Tens of thousands of people waited in line to enter St. Peter's Basilica and pay their respects to Pope Francis. Pope Francis lay in state inside St. Peter's Basilica. Picture Alliance via Getty Images