Bathyscaphe Trieste
On 23 January 1960, she reached the ocean floor in the Challenger Deep (the deepest southern part of the Mariana Trench), carrying Jacques Piccard and Don Walsh. This was the first time a vessel, manned or unmanned, had reached the deepest known point of the Earth's oceans. The onboard systems indicated a depth of , although this was revised later to ; fairly recently, more accurate measurements have found Challenger Deep to be between and deep.
Kaikō ROV
On 23 January 1960, Don Walsh and Jacques Piccard were the first men to descend to the bottom of the Challenger Deep in the "Trieste" bathyscaphe. Though the initial report claimed the bathyscaphe had attained a depth of 37,800 feet, the maximum recorded depth was later calculated to be . At this depth, the water column above exerts a barometric pressure of , over one thousand times the standard atmospheric pressure at sea level. Even at this great depth and pressure, a small flounder-like fish was seen moving away from the spotlight of the bathyscaphe. Since then, only one manned vessel has ever returned to the Challenger Deep, the Deepsea Challenger, which was piloted by director James Cameron on March 26, 2012 to the bottom of the trench.