Perhaps the most significant timepiece ever created, the Henry Graves Supercomplication will cross the block on November 11 at Sotheby’s Important Watches sale in Geneva. Conceived and built by Patek Philippe for the New York banker Henry Graves, the pocket watch has the distinction of being the most complicated hand-built watch ever made.

Commissioned in 1925, the Supercomplication required three years of research and development and another five years for Patek Philippe’s technicians to construct it. The …