In 1950, President Truman dedicated Friendship International Airport (now Baltimore/Washington International Thurgood Marshall Airport). He flew to the ceremony from Washington and was accompanied by Mayor D’Alesandro, who had never flown before. When the plane hit a series of air bumps during the flight, D’Alesandro joked to an aide, “We’re going to have to repave this.” (Baltimore Sun file photo)

1497: The first recorded sighting of North America by a European took place as explorer John Cabot, on a voyage for England, spotted land, probably in present-day Canada.

1947: In what is believed to be the first report of “flying saucers,” Kenneth Arnold, of Boise, Idaho, claimed he observed nine “shining, saucerlike objects” over Washington’s Mount Rainier.

1983: The space shuttle Challenger — carrying Sally Ride, America’s first woman in space — landed safely at Edwards Air Force Base in California.

Compiled by Laura Lefavor and Paul McCardell.