In 1875, during a global scientific expedition that had begun three years earlier, the crew of the British naval ship HMS Challenger was measuring the depths of the western Pacific Ocean. No one anticipated what they would find. On March 23, the sailors dropped a weighted rope into a location now known as the Mariana Trench. It kept sinking, unspooling for what must have felt like an eternity. The rope finally hit the bottom after falling for more than 8 kilometres, or over 5 miles. When they hauled the line back up, they found the glass thermometers attached to it had been crushed by the immense water pressure. The measurement they recorded was 4,475 fathoms. In honour of the mission and the subsequent expedition of the HMS Challenger II in 1951, the deepest point of the trench was named Challenger Deep.
The Mariana Trench
The deepest place on Earth, a scar formed by 50 million years of one tectonic plate diving under another.
The First Sounding
Part of
Frequently Asked Questions
How deep is the Mariana Trench?
The deepest part of the trench is called the Challenger Deep. The current record depth was set in 2019 at 10,927 metres (35,850 feet). If Mount Everest were placed at the bottom, its summit would still be covered by over 2 kilometres of water.
Who were the first people to reach the bottom?
The first human descent to the bottom was made on Jan. 23, 1960. Swiss oceanographer Jacques Piccard and U.S. Navy Lieutenant Don Walsh reached the seafloor inside the bathyscaphe Trieste, spending 20 minutes there.
What kind of life exists in the trench?
Despite the extreme pressure, life thrives. The deepest-dwelling fish in the trench, the Mariana snailfish, is a small, pink, translucent creature that lives at depths of over 8,000 metres. It feeds on tiny crustaceans.
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