James Stacey dives deep into the subterranean laboratories at Rolex to provide an inside look at the lengths that the brand went to to adapt its Superlative Chronometer tests to its leviathan-sized Deepsea Challenge—including an Ultra High Pressure tank developed in partnership with COMEX.

The Deepsea Challenge is tested, in land-locked Switzerland, to a level of water pressure that doesn't naturally exist anywhere on earth.