4. Berkeley Pit, Butte, Montana
This pit used to be a copper mine and is now filled with highly acidic water. That’s how it gets that weird, dangerous-looking color. It’s about 1780 feet deep, give or take a few.
5. The Kola Superdeep Borehole, Russia
It’s super deep, guys. It even says so in the name. This borehole is about 22000 feet deep, and it was dug for no other reason than scientific research about what would happen if they drilled a hole 22000 feet deep.
6. Chand Baori, Indian State of Rajasthan
This amazing 100 feet deep stairwell seems like a really bad place to fall down the stairs. It’s also one of the man-made holes on this list. Well, at least I’m assuming it is, because I doubt water can erode a perfect flight of stairs – let alone a thousand times.
7. The Door to Hell, Derweze, Turkmenistan
It’s only 98 feet deep, but it’s permanently on fire. It really does look like it’s some kind of portal into Hell, which means it’s probably safer to visit when accompanied by a priest or the guy from Doom.
