Drop Mount Everest into this crack in the Pacific and its peak would still sit two kilometers underwater. At the bottom, the pressure could crush you a thousand times over — yet life thrives there.
3 min read · 8 key facts · 7 terms decoded
Deeper Than Everest Is Tall
The Mariana Trench is the deepest oceanic trench on Earth, a crescent-shaped gash in the western Pacific about 2,550 kilometers long. Its deepest point, the challenger-deep">Challenger Deep, plunges to about 10,935 meters.
That's more than 2 kilometers deeper than Mount Everest is tall. The trench exists because of subduction — one tectonic plate grinding down beneath another.
A Crushing, Frigid World
Conditions at the bottom are brutal. The water column overhead presses down at about 1,086 bar — roughly 1,072 times normal atmospheric pressure at sea level.
It's also nearly freezing, just 1 to 4 °C. And yet life persists: researchers have seen giant single-celled xenophyophores more than 10 centimeters across, and in 2025 identified more than 7,000 new microbial species, 89% of them new to science.
The Long Race to the Bottom
The first depth sounding came from the 1875 Challenger expedition, which used a weighted rope to measure 8,184 meters. The first crewed descent followed on 23 January 1960, when the bathyscaphe Trieste carried Don Walsh and Jacques Piccard to the bottom.
Decades later, Victor Vescovo reached 10,928 meters on 28 April 2019, and in July 2022 Dawn Wright became the first Black woman to explore the trench.
Pollution in the Abyss
Even Earth's deepest point isn't pristine. Scientists found extremely elevated concentrations of PCBs — a chemical toxin banned in the 1970s — in trench organisms.
Worse, 100% of the amphipods studied had at least one piece of synthetic material in their stomachs. A reminder that human pollution reaches everywhere, even 11 kilometers down.
Key terms, decoded
Challenger
The 1875 expedition that first measured the trench's depth with a weighted rope.
Challenger Deep
The deepest point of the Mariana Trench, about 10,935 meters down.
Mariana Trench
The deepest oceanic trench on Earth, in the western Pacific Ocean.
PCBs
Toxic industrial chemicals, banned in the 1970s, found concentrated in trench life.
subduction
The process where one tectonic plate is pushed beneath another, forming a trench.
Trieste
The bathyscaphe that made the first crewed descent to the bottom in 1960.
xenophyophores
Giant single-celled organisms, some over 10 centimeters across, living in the trench.
This Quicky is an original summary based on the Wikipedia article “Mariana Trench”, available under the CC BY-SA 4.0 license.
