What Caused The Loudest Noise Ever Heard Underwater In 1997?

For any wannabe Ernest Shackleton, it might seem that the 21st century doesn't provide many opportunities left for real exploration, but don't despair as there is still one place on Earth full of unanswered mysteries.

As much as 95% of the deep ocean is unexplored, according to the National Oceanic and Atmospheric Administration, and a new documentary for The Atlantic, has highlighted one of the most baffling questions of all.