An unmanned submarine has started exploring the deepest-known chasm in the world's oceans, the Challenger Deep, in the Marianas Trench.
Nereus, the remotely operated vehicle reached the 10 thousand 600 metre mark, while the Challenger Deep extends to 11,000 metres.
At that depth, pressure is up to 1100 times the pressure at the surface.
The Woods Hole Oceanographic Institution is conducting the expedition, with a series of sea trials with Nereus, taking the vehicle through grades of ever-greater depths from 1,000 metres to the 11,000 metre ultimatum.
Nereus is the first unmanned vehicle to explore the Marianas Trench since 1995, when the Japan Agency for Marine-Earth Science and Technology brought its ROV Kaiko there.
Kaiko was lost in 2003 after the cable it was suspended from snapped.
The first and only manned expedition to the Mariana Trench occurred in 1960, when Jacques Piccard and Don Walsh traveled there in the U.S. Navy-owned bathyscaphe Trieste.