Challenger Deep

Challenger Deep got its name from the British survey ship Challenger II, which pinpointed the deep water off the Marianas Islands in 1951. Then in 1960, the US Navy sent the Trieste (a submersible - a mini-submarine designed to go really deep) down into the depths of the Marianas trench to see just how far they would go (read the original press release). They touched bottom at 35,838 ft/10,923m. That means, while they were parked on the bottom in the bathyscaphe, there were almost seven miles/11km of water over their heads!