Cardinals have no contact with the outside world after the master of liturgical ceremonies utters the words “Extra Omnes” the Latin phrase for “all out,” to ask all those present except the cardinal electors to leave the Sistine Chapel to begin the voting process.

For nearly 180 years, papal conclaves have chosen a new pope in three to five days. In centuries past, they've taken a lot longer.

With 135 cardinals eligible to vote, the coming conclave is set to be the largest in the history of the Catholic Church and one of the most unpredictable in decades.