For centuries, the North Pole remained elusive. Early attempts to reach it were primarily motivated by the search for a navigable route through the Arctic to Asia, known as the Northwest Passage. Later, explorers focused specifically on reaching the Pole...

Civil War submarine powered by hand cranks and lit by candlelight. What could possibly go wrong? Meet the HL Hunley.

The Marianas Trench is the deepest place on earth, deeper than Mt. Everest is high. The trench is where the ocean floor disappears into the center of the earth. Find out more in Season 1, Episode 2, "The Deepest Place on Earth."

A submarine implosion sounds terrifying, but what does actually happen during a submarine implosion?