Cardinals returned to the Sistine Chapel on Thursday to resume voting for a new pope and crowds flocked back to St. Peter's Square to await their decision, after the first conclave ballot failed to find a winner during a longer-than-expected voting session.

The conclave to select the next pope has begun after Catholic cardinals from across the world filed into the Sistine Chapel Wednesday before sealing themselves inside.

The papal conclave will take place as usual in the hallowed space of the Sistine Chapel. What is the history of this famous church and its artistic treasures?