The Blue Line is a rapid transit line in the Greater Boston metropolitan area, one of four subway lines operated by the Massachusetts Bay Transportation Authority (MBTA). It runs from Bowdoin station in downtown Boston under Boston Harbor to East Boston and Revere on the inner North Shore, where it terminates at Wonderland. The stop at Airport Station, with a free shuttle bus to Logan International Airport, is one of two rapid transit connections to the airport. The line was assigned the blue color in 1967 during a systemwide rebranding because it passes under Boston Harbor.