This is the opposite of buried treasure.

As humans probe further into the Earth’s most mysterious regions, explorers today are making disheartening discoveries that reveal mankind’s far-reaching impact on the environment.

Deep sea explorer Victor Vescovo, a 53-year-old financier and former Navy Reserve commander, traveled nearly seven miles to the floor of the Challenger Deep, a relatively uncharted area at the southern tip of the Mariana Trench in the Pacific. The dive on May 1, which broke a record previously set by “Titanic” director James Cameron in 2012, uncovered disheartening evidence of humans’ destructive impact on the planet: plastic bags and wrappers floating in the deepest depths of the ocean.

Traveling 35,853 feet down, Vescovo and his team also discovered four new species that may help shed light on Earth’s murky origins. Their odyssey on the submersible vessel The Limiting Factor are being filmed for the upcoming Discovery Channel series “Five Deeps Expedition.”

“Going to the extremes I believe is a natural inclination of man,” Vescovo tells CNN. “I think it is a wonderful part of human nature that makes us want to push ourselves to the limits, which has helped propel us as a species to where we are now.”

Challenger Deep was first investigated by oceanographers Don Walsh and Jacques Piccard in 1960, but this will be the first on-camera evidence of what lies at the bottom of the Pacific. The mission is to create sonar mapping at the Earth’s deepest points, including Atlantic Ocean’s Puerto Rico Trench, the South Atlantic’s South Sandwich Trench, the Java Trench in the Indian Ocean and the Molloy Deep in the Arctic Ocean.

“I criss-crossed all over the bottom looking for different wildlife, potentially unique geological formations or rocks, man-made objects, and yes, trying to see if there was an even deeper location than where the [Bathyscaphe] Trieste went all the way back in 1960,” says Vescovo.

Among the discoveries made aboard the The Limiting Factor — the world’s first titanium-hulled, two-person submersible to dive this far — were giant prawn-like amphipods and bottom-feeding sea cucumbers. The team says scientists intend to test the deep sea creatures for plastic build-up.

While there’s no telling how far those plastics drifted to end up settled at one of the lowest points on Earth, our oceans are quickly becoming one giant trash can. In the open ocean somewhere between Hawaii and California, the Great Pacific Garbage Patch, an island of garbage the size of Texas, continues to add more man-made waste to its expanding surface area. Scientists are struggling to find ways to cull its growth.

Seeing the vessel’s potential, Vescovo hopes The Limiting Factor will be used in future scientific explorations.

“It is very important to us that we show some initial scientific discoveries, just to give a small sample of what we could do if the sub was in the hands of a professional research organization,” he says. “That is my sincere hope — to sell the system to an institute, government, or individual, that can use the whole diving system to advance marine science for decades to come.”

During his four-hour trek across the ocean floor, Vescovo relished in his once-in-a-lifetime achievement.

“Honestly, towards the end, I simply turned the thrusters off, leaned back in the cockpit, and enjoyed a tuna fish sandwich while I very slowly drifted just above the bottom of the deepest place on earth, enjoying the view and appreciating what the team had done technically,” he says. “It was a very happy, peaceful moment for me. And then I came up.”