Manufacturer: Vacheron Constantin

Vacheron Costantin's Tour de l'Ile was designed in 2005. The collectible piece is also the most complicated double-face watch, and only produced in a limited edition of seven.

This 834-part watch took over 10,000 man-hours to be made and features an 18-carat silver gold dial with a hand-sewn alligator leather band and pink gold buckle.

It touts an original combination of horological complications and astronomical indications forming 16 different points, including a minute repeater, sunset time, perpetual calendar, second time zone, and a tourbillon device.

Price: $1.5 million

Image: Tour de l'Ile watches