The team spent hours at the bottom of the ocean at these locations, collecting samples, including the deepest piece of mantle rock ever collected. Back in 1960, oceanographer Don Walsh was the first to make it down to the trench successfully, reaching about 35,814 feet (10,916 m).
On May 1, Vescovo set a record for the deepest dive and deepest solo dive, using a titanium Triton submersible called Limiting Factor to descend 35,853 feet, the Five Deeps Expedition announced Monday morning.
The last time a human visited the Challenger Deep was Canadian filmmaker James Cameron, who reached a depth of 35,756 feet in his submersible in 2012.
Down there he found wonderful sea creatures, but also found a plastic bag and sweet wrappers.
The team also found what they think are four new species of amphipods, or shell-less crustaceans.
"It's nearly indescribable how excited all of us are about achieving what we just did", Vescovo said.
Discoveries in the Challenge Deep included "vibrantly colorful" rocky outcrops that could be chemical deposits, prawn-like supergiant amphopods, and bottom-dwelling Holothurians, or sea cucumbers. "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".
Making multiple trips almost 11 kilometers, or seven miles, to the ocean floor - one of them four hours in duration - Vescovo set a record for the deepest solo dive in history, his team said.
Millions of tonnes of plastic enter the oceans each year, but where it all goes it a bit of mystery.
From behind the glass of a submersible created to withstand extreme pressures, he spent hours observing and documenting the quiet, dark alien world.
His voyage, in a submersible named The Limiting Factor, is part of a landmark odyssey into the world's watery depths that's being filmed for Discovery Channel - dubbed the Five Deeps Expedition. The pressure at the bottom of the ocean is equal to about 50 jumbo jets piled on top of a person, according to BBC News.
As well as working under pressure, the sub has to operate in the pitch black and near freezing temperatures.
Also, bathometric scanning of the Mariana Trench has given scientists a clear picture of what the Mariana Trench looks like for the first time.
The Five Deeps is the underwater equivalent of climbing the Seven Summits, which is reaching the tallest peaks on all seven continents.
These conditions also made it challenging to capture footage - the Five Deeps expedition has been followed by Atlantic Productions for a documentary for the Discovery Channel. Atlantic Productions for Discovery Channel/Handout via REUTERS.
When the Five Deeps expedition is complete, the researchers plan to pass their findings onto science institutions, which will continued to use their information for studies.
The challenges of exploring the deep ocean - even with robotic vehicles - has made the ocean trenches one of the last frontiers on the planet.
Deep sea dives have proven that areas thought to be remote and desolate are actually filled with life - and apparently, pollution. There is also growing evidence that they are "carbon sinks", or natural environments that store carbon, which play a role in regulating the Earth's climate.