Leo's discharge capped days of uncertainty that rattled the Vatican and the world's 1.4 billion Catholics, less than two years into the Chicago-born pope's papacy.

Leo's discharge capped days of uncertainty that rattled the Vatican and the world's 1.4 billion Catholics, less than two years into the Chicago-born pope's papacy.

The 71-year-old pope was seen crossing the lobby of the Gemelli hospital on foot and exiting the building, smiling as he shook hands and waved.

The 71-year-old pope was seen crossing the lobby of the Gemelli hospital on foot and exiting the building, smiling as he shook hands and waved.

The Pope has left Rome's Gemelli hospital four days after undergoing surgery for lung cancer, and returned to the Vatican.