Francis’ successor will be selected by cardinals at the conclave that begins on May 7. Cardinals, known as the “princes of the church,” rank just below the pope in the Roman Catholic Church; together, they are known as the College of Cardinals. When a pope dies, the college chooses a successor.

Among the massive crowds of people waiting for the first round of smoke to emanate from the chimney of the Sistine Chapel, several Filipino Catholic pilgrims were hoping for the Church to be led by a pope who is one of their own: Cardinal Luis Antonio Tagle.

Throughout the 20th century, only two conclaves lasted up to five days − Pope Pius X's election in 1903 and Pope Pius XI's election in 1922.

White smoke will soon rise again from the Sistine Chapel chimney, signaling a new era of leadership in the Catholic Church — but first, there must be prayers, meetings and a highly secretive conclave.

From conclaves to reincarnation, religious traditions around the world follow different rules when selecting new spiritual leaders. Here’s how major religions make their choices.