Pope Francis's death at the age of 88 means the Catholic Church must choose a new leader. Here's how cardinals elect the next pontiff at the conclave.

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.

Simply put, a conclave is the assembly of cardinals that elects a pope. The word itself comes from the Latin "com" and "clavis," meaning "together" and "key," respectively – highlighting the absolute, behind-closed-doors secrecy with which the cardinals conduct their discussions and balloting.