Explorer Victor Vescovo also discovered four new crustacean species in his descent 11 kilometres down into the deepest part of the ocean on the third Mariana Trench expedition since 1960.
From behind the glass of a submersible created to withstand extreme pressures, he spent hours observing and documenting the quiet, dark alien world.
Over four hours exploring the seabed of the trench he saw sea creatures, plastic bags and lolly wrappers. Once he finishes his last dive in August, he will be the only person to ever summit the highest mountain on each continent and go to the lowest point of each ocean.
The last visit to Challenger Deep also set a depth record at 35,787 feet.
The dive was the first for The Five Deeps Expedition, funded by Vescovo, and is being filmed for a Discovery Channel documentary.More news: Liverpool fall short of title despite Mane double against Wolves
"It is nearly indescribable how excited all of us are about achieving what we just did", Vescovo told the BBC.
He explained the expedition "took marine technology to a ridiculously higher new level by diving - rapidly and repeatedly - into the deepest, harshest, area of the ocean".
Witnessing the dive from the Pacific was Don Walsh.
A robotic lander photographs the creatures in the deep Mariana Trench and the submersible in the background.
The Five Deeps dive to Challenger Deep in the Pacific Ocean broke a new record.
"Now in the winter of my life, it was a great honour to be invited on this expedition to a place of my youth".More news: Mariana Trench: Deepest-ever sub dive finds plastic bag
His team believes they discovered four new prawn-like species in total.
In the depths, during those five dives, they discovered red and yellow rocky outcrops that could be chemical deposits or bacterial mats, which are made by chemosynthetic microbes, meaning they can convert carbon-containing molecules into organic matter.
After spending hours crisscrossing the bottom of the Challenger Deep, collecting video evidence of different wildlife, geological formations and man-made objects, Vescovo stopped for a second.
The team said its scientists were going to perform tests on the creatures found to determine the percentage of plastics found in them.
An American explorer has broken the the record for the deepest ever dive.
On April 28, in the middle of the Pacific Ocean, Victor Vescovo climbed into the cramped cockpit of his personal $48 million submersible and descended beneath the waves deeper than any human being had been.More news: Monsanto to pay US$2 billion in Roundup weed killer cancer case
At the deepest point, they were accompanied by some transparent bottom-dwelling sea cucumbers (Holothurians) and an amphipod called the Hirondellia gigas.