Patek Philippe, World Time, Complications, ca 2010.

In 2006, Patek Philippe introduced the reference 5130, a significant addition to their esteemed lineage of world time wristwatches that included predecessors like the references 1415 HU and 2523. The roots of the 5130's world-time mechanism can be traced back to the 1930s when the ingenious watchmaker from Geneva, Louis Cottier, crafted a remarkably slim mechanism. This mechanism accomplished a feat: it simultaneously displayed the correct time across the various time zones of the world through a revolving 24-hour ring while also indicating the local time.

The 24-hour chapter-ring, with its concentric layout, elegantly segregates day and night hours. The local time zone takes center stage at the 12 o'clock position, with the hour and minute hands dutifully aligned to the local time. What makes this design truly remarkable is its ability to showcase the precise time, including both hours and minutes, for every time zone worldwide, all on a single dial with clear indications of the local time. This ingenious mechanism, initially conceptualized by Cottier, eventually led to a patent secured by Patek Philippe in 1959. The culmination of this innovation was the introduction of the calibre 240 HU in 1999, cementing Patek Philippe's enduring legacy in the world of horology.