Girard-Perregaux manufactured a 50 piece limited edition watch to commemorate John Harrison’s sea voyage in November 1771 from Portsmouth, England to Port Royal Jamaica. John Harrison is the creator of the H-4 watch which measures the ship’s longitude to within half a degree.

The watch’s dial is made from champlevé enamel which shows the journey taken by Harrison from Europe to America.

http://thewatchlounge.com/girard-perreguax-ww-tc-john-harrison-limited-edition/