The most complicated handmade watch, the Henry Graves Supercomplication, has been sold at auction for 20.6m Swiss francs (£13.4m)
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.
But for a "very flamboyant time he was a strangely quiet man", says Stacy Perman, author of A Grand Complication. His father was a "figure of the gilded age of American finance", but Graves was more a man of leisure. He was a banker, but not "nine to five", notes Perman.
This was the tail end of the "golden age of watchmakers". "Until the advent of the automobile they were considered the most innovative makers in the world," Perman explains.
Graves was an "incredibly keen" sportsman, which may have drawn him to the increasingly competitive field of watchmaking. The Geneva Observatory Timing contest, the "watch Olympics" as Perman calls it, pitted timepieces against each other for prizes and Graves took a close interest in it.
BBC News - The story of the 'most complicated' watch in the world