The cardinals responsible for electing a new pope are locked inside the Sistine Chapel for the secret ballot.
Black smoke means more voting will take place tomorrow, white means there is a new pope.
Before the doors shut, cardinals took an oath in which they promised to keep secret all matters related to the vote and that whoever is elected will faithfully carry out the role.
They will now have no communication with the outside world until a new pope is elected, meaning the conclave has officially begun.
Because a new pope requires a two-thirds majority, the process can take some time, although the last two conclaves concluded by the end of day two.
To cast their vote, each cardinal casts their vote on a card that says in Latin “I elect as Supreme Pontiff” alongside the name of their chosen candidate.
They walk in order of their seniority to place their cards inside the large silver and gilded urn.
(BBC News)
