Historic map of the Mariana Trench. NOAA / Wikimedia Commons.
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The Mariana Trench in the western Pacific contains the deepest known part of Earth’s oceans. Its lowest measured region, Challenger Deep, lies nearly 11 kilometres below sea level. Pressure there is more than a thousand times atmospheric pressure at the surface, and sunlight cannot reach the bottom. Yet life exists even in these extreme conditions. In 1960, Jacques Piccard and Don Walsh descended to Challenger Deep in the bathyscaphe Trieste. Decades later, improved submersibles allowed further scientific exploration. The trench reminds us how much of the deep ocean remains difficult to observe directly.
