Victor Vescovo completed a record-breaking dive to the Challenger Deep on April 28, 2019 (Credit: Five Deeps Expedition)

For most people, completing the "Explorers Grand Slam," which requires climbing the Seven Summits — the highest mountain in each of the seven continents — and reaching the North and South Poles, would be achievement enough. However, not for American explorer and adventurer Victor Vescovo, who completed the challenge in 2017. Since December 2018, the 54-year-old former US naval officer has been on a new quest — to become the first person to take a manned submersible to the deepest-known point in each of the world's five oceans.

On April 28, 2019, the daredevil came one step closer to accomplishing his goal when he descended 10,928 meters (35,853 feet) aboard Limiting Factor, a 15-foot long, 12-foot-high submersible, to the Earth's deepest known point - the Challenger Deep. In addition to establishing a new world record for the deepest human dive, Vescovo also became the first person in the world to reach the planet's highest (Mt. Everest) and lowest (Challenger Deep) points.

The Challenger Deep is the Earth's deepest known point (Credit: I, Kmusser/ commons.wikimedia.org/CC BY-SA 2.5)

Located in the Mariana Trench, a 1,500-mile scar in the Pacific seafloor, the 6.8-mile-long opening has only been visited twice before by humans. In 1960, the now-retired U.S. Navy Captain Don Walsh and Swiss engineer Jacques Piccard made it to a depth of 10,912 meters (35,800 feet) aboard their submersible Trieste. Though they remained there for about 20 minutes, their view of the dark and mysterious world of the Challenger Deep, which measures 50 times larger than the Grand Canyon, was obscured by the silt stirred up during the landing.

In 2012, James Cameron, the genius behind Hollywood blockbusters like Titanic and Avatar, became the first person to descend to the Challenger Deep solo aboard the Deepsea Challenger submersible. The expert diver, who reached a depth of 10,908 meters (35,787 feet), spent three hours observing the desolate, almost viscous, landscape. However, he did not see any mysterious alien creatures — only tiny shrimp-like crustaceans measuring less than an inch in length.

Vescovo found evidence of marine life at the bottom of the Challenger Deep and even some human-generated trash (Credit: Five Deeps Expedition)

Cameron's record was, of course, surpassed by Vescovo's solo dive on April 28, 2019. However that was not the adventurer's only visit to the Challenger Deep. Vesocovo returned to the area three more times in the next eight days and on May 7, 2019, he became the first human to descend to the Sirena Deep, another fissure in the Mariana Trench, and collect the deepest piece of mantle rock ever recovered. While the first two excursions were undertaken alone, during the final three, Vescovo was accompanied by another member of his crew.

“It is almost indescribable how excited all of us are about achieving what we just did,” said Vescovo. “This submarine and its mother ship, along with its extraordinarily talented expedition team, took marine technology to a ridiculously higher new level by diving—rapidly and repeatedly—into the deepest, harshest, area of the ocean.”

Unlike previous Challenger Deep visitors, the "Five Deeps Expedition" team, who stayed underwater for an average of three hours during each dive, noticed several new species. Among them were four types of crustaceans known as amphipods, as well as a Holothuria, a translucent version of a sea cucumber or sea pig. What put a slight damper on the otherwise successful mission was the sight of what appeared to be litter. Vescovo told Forbes Magazine, " I’m not quite sure what it was. One of the items looked like a square. It could have been plastic. It definitely wasn’t metal. It just looked like trash. The other item looked like a triangle. It had a sharp edge, so it was definitely man-made. It also had a discernable imprint of a stylized "s," and it looked like a container of some sort. It probably was plastic, but I don’t know for sure."

A new species of jellyfish was spotted in Indian Ocean's Java Trench (Credit: Five Deeps Expedition)

The latest diving adventure is the fourth Vescovo has completed since embarking on the Five Deeps Expedition in December 2018. Prior to this, the adventurer successfully entered the Southern Ocean's 23,737- foot-deep (7,235 meter) South Sandwich Trench, the Atlantic Ocean's 27,480-foot-deep (8,376 meter) Puerto Rico Trench, and the Indian Ocean's 23,612 foot-deep (7, 197 meter) Java Trench. Next up is the mission's fifth and final dive — the Arctic Ocean's 17,881-foot-deep (5,450 meters) Eurasian Basin.

Once done, the American explorer, who funded the $50 million Five Deeps Expedition with his personal money, has his sights set on space. He told Forbes, "No one has done the so-called trifecta – the top and bottom of the world and space. For me, that would mean getting to the Karman Line, 100 km [62 miles] above Earth. But the real gold standard for me would be orbit. I’d love to see the sunrise from there, at least once, like the astronauts have. I think that would be lovely."

Resources: Forbes.com, USAtoday.com, Wikipedia.org, the engineer.co.uk