The 10 Spookiest Holes on Earth (and Beyond)

9. Berkeley Pit Mine (Butte, Mont.)

The Berkeley Open Pit Mine is America's largest Superfund toxic-clean-up site, and Montana's dumbest tourist attraction. For $2, you can access an observation platform to look at what is essentially an incredibly poisonous and ugly hole in the ground. The viewing platform over the hole is about as close as you'd want to get to the Berkeley Pit, given that the water is so acidic and rich in heavy metals that if you drink any, it will literally corrode you from the inside out. Noisemakers and guns loaded with blanks are positioned around the pit to scare off migrating waterfowl ever since at least 350 snow geese landed in the lake in 1995 and basically melted.

8. 2008 Daisetta Sinkhole (Daisetta, Texas)

Due to the salt dome underlying the town of Daisetta, it's had multiple major sinkholes over the years, but the 2008 event was considerably more dramatic than most, suggesting renewed anger on the part of the Kingdom of the Mole People. The 2008 sinkhole started as your everyday, nothing-to-worry about pit of wreckage appearing out of nowhere, measuring barely 20 feet across. By the same time the next day, however, the hole had expanded to 900 feet in diameter and 260 feet deep at the epicenter, menacing a nearby factory and high school. Geologists believe the sinkhole was caused by local oil rigs pumping saltwater and other waste byproducts into the salt dome, as well as local saltwater injection rigs used for natural-gas production. The city and 200 of its residents have brought a class-action lawsuit against ExxonMobil and the other petrochemical companies that were carrying out these activities without a license. But it's Texas. They'd probably have better luck trying to sue the Kingdom of the Mole People.

7. Derweze Flame Cavern (Karakum Desert, Turkmenistan)

In 1971, a drilling rig near the tiny settlement of Derweze ruptured an underground cavern full of gas vapor, creating a hole full of poisonous gas some 70 meters across. Any attempt to collect the gas vapor would release a great deal of toxins into the local town, so Russian engineers decided to ignite the gas cavern in the belief that it would burn itself out in a matter of days. 40 years later, the semi-nomadic citizens of Derweze still find themselves neighbors to an oddly picturesque flaming hole in the ground. Known popularly as "The Door to Hell," the Derweze pit has become a sort of hyper-exotic tourist attraction. Unfortunately for spooky-hole fans, the current Turkmenistani government is determined to develop the Karakum Desert's natural-gas reserves on an industrial level, and gigantic open pits of eternal flame are frowned upon in that sort of development, so it's likely that steps will be taken to close the Door to Hell forever.

6. Samaesan Hole (Samaesan, Thailand)

Samaesan Hole is a 90-meter-deep dive site located in an active shipping channel between the islands of Ko Chuang and Ko Samae San. What sort of interesting stuff can you find in Samaesan Hole? Bombs. Samaesan Hole is an ammo dump site for the Thai military, and is marked on charts as containing unexploded munitions. Adding to the fun is the enormous amount of dive gear required to look at all the things that could explode at any moment. By the time divers are ready to make the descent, they're closer in size and maneuverability to tiny submarines, but it's all worth it to dive down there and maybe get blown up.

5. Sima Humboldt (Sarisarinama Tepui, Bolivar, Venezuela)

The tepuis of Venezuela are some of the most unique geographical features in South America. Tall, flat-topped, forested buttes, these mountains host strange ecosystems isolated from the normal life of the jungle by the imposing cliff walls. Sarisarinama Tepui, a 3,500-meter-tall mountain hundreds of miles from the nearest road, is home to bizarre and fascinating sinkholes or "simas." Sima Humboldt, the largest of these, is so big that it has its own ecosystem at the bottom, isolated from Sarisarinama just like Sarisarinama is isolated from the rest of the forest. Sima Humboldt is also unusually round and looks almost man-made from the sky, which, if the History Channel has taught us anything, means that it is the work of ancient aliens.

4. Cave of the Crystals (Naica, Chihuahua, Mexico)

Everyone who's watched a fantasy movie from the '80s or had a hippie aunt knows that crystals are powerful objects with the ability to heal chakras and destroy wizards. Unfortunately, most crystals are itty-bitty things suitable only for hanging from dreamcatchers. There's only one place to go if you need to really impress a hippie or scare a wizard, and that's the Cave of the Crystals off of the Naica mine complex. Unfortunately, the environment of the cave is so hostile to human life that you're likely to die within 15 minutes. A magma chamber just beneath the cavern floor keeps temperatures at the 130-degree level and humidity at an incredible 95 percent, effectively preventing the human body from shedding waste heat. Exploration is possible only with specially designed coveralls packed with frozen gel and special respirators to chill the air and filter out particulates, and even then you only get a little less than an hour before the suit begins to fail. It's a hell of an effort to just stay alive, but if you can sneak a hacksaw past the team of scientists monitoring the crystals, you can come back with a really awesome paperweight.

3. The Black Hole of Andros (South Andros, the Bahamas)

The Andros Archipelago is a mostly untouched wilderness reachable only by various combinations of aircraft, boats and unpleasant hikes, so it's not too surprising that its dozens of mysterious sinkholes were first noticed only in 1985, and first explored in 1999. Geobiologist and world-renowned cave diver Dr. Stephanie Schwabe launched an expedition to the largest of the sinkholes. After descending into the dim but clear water, Schwabe and company discovered a hot, jelly-like layer of bacteria that formed a barrier between a relatively normal environment above and a pitch-black, oxygen-free zone beneath, where hydrogen sulfide (a lethal neurotoxin) slowly soaked through the divers' skin. Deciding this was not a great place to hang around, the team returned to the surface to discover all their silver or chrome-plated metal had turned black during the brief time away. Subsequent testing has not yet determined if the divers were also driven mad by the chanting of ageless evil beings who dream of a world free of cursed sunlight, but the smart money is on "probably."

2. The Blue Hole of Sinai (Dahab, Egypt)

The Blue Hole of Sinai is popularly known as the "World's Most Dangerous Dive Site" for the number of scuba divers who've met their fate there. While official Egyptian tourism board sources say 40 people have died in the Blue Hole, locals and experienced dive guides figure at least twice that many were lured to their deaths by the Stygian sinkhole. Despite its depth of 130 meters, the most dangerous feature is an underwater tunnel known as the Arch, which connects the deeper parts of the Blue Hole to the ocean via a dark and treacherous passage through a coral reef. The Arch is just beyond the official recreational diving limit of 40 meters. It's the level at which the mind-bending effects of depth and nitrogen oversaturation leave unsuspecting divers barely able to spell their own names, let alone navigate an underwater tunnel. In many cases (like the chilling recorded death of amateur diver Yuri Lipski), divers are so zonked out by nitrogen narcosis that they miss the entry to the Arch entirely, and keep swimming down until they pass out and asphyxiate.