Fasten your seatbelts for the story of the Rolex GMT-Master. Aviation company Pan-Am requested Rolex to create a wristwatch that would display multiple time-zones simultaneously, as their flights got longer; crossing multiple time-zones. Rolex came up with the GMT-Master (GMT’ stands for Greenwich Mean Time’) in 1954. The watch features a date-function and an extra hour hand (with triangle) that points out the second time zone on the bi-directional turning, 24hour bezel.