Deep within Rolex's landmark Geneva HQ is a 1.3 tonne lump of stainless steel. Somewhat unprepossessing from the outside, inside is a hostile microcosm.
The tank simulates pressure at 16,000ft below sea level and it is inside that Rolex's Deepsea watches are tested before release onto the market.
It is, potentially, an expensive process. The smallest flaw in each watch's construction will make it explode, so it pays to make sure everything is right before undergoing this hyperbaric assault.