In another EarthDate, we talked about Challenger Deep, the deepest point in all the oceans, at almost 7 miles down.

The first humans to explore it were a Swiss oceanographer and U.S. Navy Lieutenant. They built a special deepwater submarine called a bathyscaphe, and in 1960, headed for the bottom.

It took them 3 hours to reach the western pool of Challenger Deep at 35,000 feet. But they stirred up so much sediment, they couldn’t see anything.

That, and a worrisome crack in a window, cut their trip short. After 20 minutes, they jettisoned their ballast and began their 2-hour trip to the surface.

The next visit came 50 years later, when film director James Cameron co-designed his own ultradeep submersible and captained it solo into the deeper Eastern pool, at 35,800 feet.

He spent 2 hours motoring slowly around the bottom, taking photos and video, but didn’t see any creature longer than 1 inch.

Recently, explorer Victor Vescovo piloted his craft slightly deeper than Cameron, now holding the world record. His scientific team then made a few more trips to the bottom, discovering a new species and gathering samples.

They found small crustaceans with high concentrations of chemicals banned in the 1970’s. And, a plastic candy wrapper.

A reminder that, even in places where humans can scarcely visit, our impact can be seen.