Biscom, a Milan-based broadband cable operator whose stock is currently buried in a deep trench, along with a host of other, bigger telecom companies.

FORBES: A fiber niche is nice

But it was only three years ago that vents were first detected in the Cayman Trough, a deep trench formed by the boundary between two tectonic plates.

BBC: Deepest undersea vents discovered by UK team

On a recent tour of a 500-foot-deep Bahamian trench Hawkes surprised a shark that hadn't sensed the Aviator's presence.

FORBES: Cruising Altitude: Minus 400 Feet

In 1960 Don Walsh, along with Jacques Piccard, undertook an eight-and-a-half hour decent in the bathyscaphe Trieste to the deepest part of the ocean, the 10, 911 metre (36, 000ft) Challenger's Deep in the Mariana Trench off the coast of the Phillipines.

BBC: Voyage to the 'real' North Pole

The billionaires are bankrolling expeditions to reach the deepest place in the ocean, a spot called the Challenger Deep that lies at the bottom of the Mariana Trench, seven miles below the surface of the South Pacific.

FORBES: Branson And Schmidt Race To The Bottom Of The Ocean