The Hadal Deep
The Hadal Deep is technically a joint moniker for the deepest parts of the ocean all around the world, but the Mariana Trench is where it is at its absolute most unforgiving. The zone is named after the Greek mythology’s underworld Hades, and fittingly enough, it’s so intensely hostile to human life that more people have been to the Moon than ventured there. This is a big part of why it holds so many mysteries: To keep people alive (and equipment intact) in the pressures of the Hadal Deep is intensely difficult.
Oh, and here’s where things get really nasty: When it comes to the Mariana Trench, the beginning of the hellish Hadal Deep is pretty much just the halfway point. The Hadal Deep starts at 20,000 feet below the surface, while the deepest (as far as we know) parts of the Mariana Trench are well over 35,000 feet deep. So, before you venture there, maybe do a practice run in one of the other 45 Hadal areas in the world.
Yes, you read that right. There are no less than 46 of these underwater hells scattered around the world, and we’ve barely scratched their surface.