The deep ocean is the Earth's last great unexplored frontier... The ocean covers nearly three-quarters of the Earth's surface yet more than 80% of it remains unexplored…We have more accurate maps of Mars than we do of two-thirds of our own planet.
No one had ever reached the deepest points in all five oceans. So in 2015 Victor Vescovo hired Triton Submarines, a company that makes private submersibles, to build him a craft that could take him to them.
Apart from Vescovo's, fewer than ten manned craft are currently able to operate below 3,700 metres, the ocean's average depth, and no other active ones can go below 7,500 metres. At that point, submariners enter what oceanographers call the Hadal Zone, derived from Hades – the Ancient Greek underworld. The ocean's deepest point, the Pacific's Challenger Deep, is nearly 11km down. When Vescovo set out, only three men had ever seen it. Twelve have walked on the Moon.
See the whole article on The Economist here: The last of the great explorers
