First released in 1955, the original GMT-Master was designed to serve international pilots by allowing them to track time in multiple timezones when intercontinental air travel picked up in the 1950s with the emergence of the Jet Age. It was also the official watch of many intercontinental airlines like Pan Am (Pan American World Airways). The GMT-Master II was launched in 2005 and continues to carry on the invaluable utility of the original GMT-Master. Though designed for professional use, the GMT-Master II has become especially popular over the years for its bold, sophisticated look.