The story of the 'most complicated' watch in the world
A "complication" is a technical term referring to any feature on a watch which is in addition to simply telling the time - and Henry Graves Jr wanted more than anyone else.
The Supercomplication, made by Patek Philippe in 1932, has 24 of them including Westminster chimes, a perpetual calendar, sunrise and sunset times, and a celestial map of New York as seen from Graves's apartment on Fifth Avenue.
It was commissioned in 1925 but was not delivered to [Graves] until 1933. It has 900 parts and remains the most complicated watch built without the assistance of computers, according to Sotheby's. One of its functions shows sidereal time, which is based on the amount of time it takes the Earth to make two consecutive transitions of a meridian by a fixed start. A sidereal day is approximately 23 hours, 56 minutes and 4.1 seconds.
It was last wound in 1969. And it's still working.