The Henry Graves Supercomplication made by Patek Philippe in 1933 © Sotheby’s

Sotheby’s announced that at the November 11th auction in Geneva, they will have the honour to present The Henry Graves Supercomplication, a Patek Philippe pocket watch made in 1933, considered to be the most complicated watch ever made entirely by human hand.

Last time, it was on the market, it was 15 years ago, also a Sotheby’s auction. At that time, it was expected to sell for $3-5 million, but after an extended bidding contest it sold for a record-breaking $11 million, becoming the most expensive timepiece ever sold at auction.

At the November auction — that also coincides with the 175th anniversary of Patek Philippe — the watch will be offered in Sotheby’s Geneva sale of Important Watches with an estimate in excess of $16 million.

A close-up of the Henry Graves Supercomplication with the night sky of New York City ©Sotheby’s

In 1925, Patek Philippe was commissioned by Henry Graves, a prominent New York banker, to produce the most complicated watch in the world. The product of three years of research and five years’ effort by the most skilled technicians, this extraordinary timepiece is a gold openface minute repeating chronograph clockwatch with Westminster chimes. Among the features it incorporates there is a perpetual calendar, moon phases, sidereal time, power reserve, and indications for the time of sunset and sunrise and the night sky of New York City. With a total of 24 horological complications, The Graves watch retained the title of the world’s most complicated watch for 56 years and even then was only surpassed by technicians working with the aid of computer-assisted machines.

UPDATE: The winning bid came from an anonymous buyer who paid 23,237,000 Swiss Francs, equivalent to USD $24 million at the time, the highest price that was ever paid for a wristwatch or a pocket watch.