Star watch: Midnight Planétarium from Van Cleef & Arpels
Watching the rotation of five planets
As well as showing numerical time, the watch displays the rotation of five planets including Mercury, Venus, Earth, Mars, Jupiter and Saturn.
Each of the featured planets are designed using precious and semi-precious stones, and cleverly rotate around the sun - which is placed in the centre of the watch - in the same time the planets they represent move in reality.
Denis Giguet, Van Cleef's master watchmaker, revealed that one of the biggest challenges in creating the watch was making the planets rotate correctly in such a small frame.
The Van Cleef & Arpels Midnight Planétarium retails for $245,000.