What is a plenary indulgence?

20200326T1020-1272-CNS-PLENARY-INDULGENCE

A man prays in front of an empty St. Peter's Square in Rome March 25, 2020. Pope Francis said he will grant a plenary indulgence to the faithful who watch or listen to his extraordinary blessing "urbi et orbi" (to the city and the world) at 6 p.m. Rome time March 27. (CNS photo/Guglielmo Mangiapane, Reuters) See PLENARY-INDULGENCE March 26, 2020.