Billionaires have started their own space race, yet more men have stepped on the moon than have gone to the deepest part of the ocean floor.
Maybe that's why it has become the next frontier for the wealthy. Dozens of the world's wealthiest individuals own submersibles, like Microsoft co-founder Paul Allen's $12 million yellow submarine.
The most cutting edge of these private subs are being created in the San Francisco Bay Area at Hawkes Ocean Technologies.
For $5 million to $10 million a piece, they build subs with wings. They "fly" through the water with fingertip control.
"Everyone loves to fly and flying underwater is even better than flying in air because there are things around you," says Graham Hawkes, owner of Hawkes Ocean Technologies.
The wing changes the underwater experience from sinking to swimming, the same way the Wright brothers used wings to change flying from balloons to airplanes. So now you can fly through the water with the fish.
"The markets are pretty much coming to us, which is nice," Hawkes' wife Karen said.
The most extreme version of Hawkes' subs is the Deep Flight Challenger, a high-speed submersible still under construction that was being built for multi-billionaire adventurer Steve Fossett.
Fosset broke several records in the air and on the water. But he also wanted to become the first person to go solo to the very bottom of the Mariana Trench — more than 36,000 feet below sea level.
Last week, Fossett was declared legally dead, having gone missing since a September flight over Nevada. But the construction on his special submersible continues as the company looks for a new buyer.
"Sorry to lose the guy," Hawkes said. "There's nobody on this planet replacing him."