Fifty years ago this week, two explorers made made the first descent of a vessel, manned or unmanned, to the deepest point of any ocean - a place where no one had been before, nor has been since.
On January 23 1960, Swiss engineer Jacques Piccard and US Navy Officer, Don Walsh travelled 11km down to the bottom of the Challenger Deep in the Marianas Trench of the Pacific Ocean in the Trieste, a specially designed deep sea diving vessel.
The expedition proved that life can survive in the extreme depths, with the hydronauts, seeing "weird white fish at the bottom," (Observer, January 24 1960.) This discovery was an important argument against the dumping of nuclear waste in ocean trenches.
A Japanese robotic craft, Kaiko, reached the bottom of Challenger Deep in 1995, and another visitor, Nereus, a remotely operated hybrid, touched down on May 31, 2009. Trieste's record may never be broken though due to the fear of a craft imploding. Those who have tried to repeat the amazing record all turned back at the 7.9km mark.