Vanessa O’Brien was headed into the unknown. It was June 2020, and O’Brien and pilot Victor Vescovo were crammed inside a small deep-sea vehicle called a submersible.
Eight years earlier, O’Brien had climbed to the summit of Mount Everest, the world’s highest point. Now she was trying to reach its lowest: Challenger Deep. That’s the deepest part of the Mariana Trench, a long, narrow canyon in the Pacific Ocean.
O’Brien and Vescovo’s sub was lowered into the water by a crane from a ship. Within minutes, the deep blue of the ocean turned to pitch-black. As the sub slowly descended, the water got darker and colder. After four hours, Vescovo said, “Touchdown!”
They had finally reached the deepest known spot on the planet.
“The bottom looks a little bit like what I imagine the moon to look like,” says O’Brien. “It’s very still. This is an uninterrupted, unvisited place.”