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.

More than 130 Catholic cardinals on Wednesday began the secretive, centuries-old ritual to elect a successor to Pope Francis, opening the most geographically diverse conclave in the faith’s 2,000-year history.

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?