Following a lengthy hospital stay for a critical respiratory problem, Pope Francis greeted parishioners gathered for Sunday Mass in St. Peter's Square.

Marking another in a series of recent surprise public appearances, Pope Francis on Sunday briefly greeted thousands of pilgrims gathered in St. Peter's Square to celebrate Palm Sunday.

Pope Francis made a brief appearance in St. Peter's Square on Sunday at the end of a Palm Sunday service, greeting the crowds from his wheelchair as he continues to recover from double pneumonia. "Happy Palm Sunday,