While us humans continue to search for resources, we're not going to have a shortage of strange holes that seemingly open up out of nowhere. From fiery pits that look like the gates of hell opening up on Earth, to caves that will leave you in bat country - here is our pick of the strangest holes on Earth.
Serra Da Estrela Mountain (Portugal)
Serra Da Estrela, roughly translated to "Star Mountain Range", is the highest mountain range in Continental Portugal. Surrounded by natural beauty and a landscape more or less that remains untouched by man, the sinkhole that occurs here is no less beautiful than its surroundings. Filled with vegetative growth, this sinkhole may very well be our favorite as far as the tranquility it has. With little tourism, most pictures are captured using the aid of surveillance drones and other aerial vehicles.
Well of Chand Baori (India)
The stepwell of Chand Baori, one of the largest stepwells in the world and also one of the most beautiful, can be found in the village of Abhaneri in Rajasthan. It was built during the time of King Chanda, sometime between 800 and 900 AD. The sides of the well are lined with steps, some 3,500 of them, that take you down 20 meters or about 66 feet below the surface. During ancient times, the Well of Chand Baori was used as a gathering hall of sorts at night, and as a source of water for the locals in the surrounding areas during the day.
Guatemala Sinkhole (Guatemala)
With a large city, mostly built on top of material such as volcanic pumice and limestone, it is no surprise that Guatemala City has experienced its fair share of sinkholes before in the past. But when it comes to the sinkhole known as "The Guatemala Sinkhole", this is a beast of a whole different nature. Back in May of 2010, a 60-foot or roughly 18-meter hole, would suddenly open up in the middle of Guatemala City, and consume everything above it, including an entire 3-story building and a nearby house. When sinkholes like this one open, it happens so instantly, that there's hardly a moment to spare to even think of escape.
Diavik Mine (Canada)
The Diavik Diamond Mine would come into existence after four diamond-bearing deposits called kimberlite pipes were discovered in 1994 and 1995. Producing some highly regarded stones for the commercial marketplace, with most having the desired white color and hefty weight of one karat or larger, it would seem that this mine is nowhere close to shutting its doors. Dominion Diamond Corporation, the owners of the mine, say the current mine plan is to continue production until 2023.
Devil's Sinkhole (Texas)
Home to one of the planet's largest concentration of the Mexican Free-Tailed bats, this enormous cavern is known as the "Devil's Sinkhole", and it's the largest single chamber cavern in the state of Texas. Sporting a gaping 50-foot or roughly 15-meter opening, the cavern drops down 140 feet or 43 meters, where it bellows out to an impressive chamber, spanning close to 320 feet or about 100 meters wide. It is truly a site of natural beauty, as many of the hundreds of thousands of tourists would probably attest to.
El Zacaton Cenote (Mexico)
The El Zacaton Cenote is known to be one of Mexico's popular landmarks, largely in part to that fact it's the deepest water-filled sinkhole on Earth that we know of, measuring an astounding 339 meters or a little over 1,100 feet deep. A cenote is a natural pit or sinkhole that forms when limestone bedrock crumbles, revealing groundwater underneath. As you can see with the El Zacaton cenote, the water is clear and pure; as are most cenotes.
Kimberley Diamond Mine (South Africa)
Diamonds are forever, as the old adage goes, but it seems that the mines they come from, are not. In South Africa you would find the Goliath hole known as the Kimberley diamond mine, once the largest of all the diamond-producing mines in the world. Shut down in 1914, the mine measures roughly 1 mile or 1.6 kilometers in circumference, and has since been known only as the "big hole" by locals. The incredible part about this mine is that it was dug by hand; about 50,000 pairs of hands that is, using only picks, shovels and other hand tools from the span of 1871 to 1914.
Darvaza Gas Crater (Turkmenistan)
There are few places on Earth that make you feel uneasy; there are even fewer places that seem almost nightmarish; the Darvaza Gas Crater, is one of the latter. Dubbed "the door to hell" and "the gates of hell" by the locals, the pit of hell-fire first came into existence in 1971 after the Soviet Union began looking for oil fields in the desert. Thinking they found oil, they began drilling; unbeknownst to them, they began drilling into a cavern filled with natural gas, which couldn't support the weight of their equipment and collapsed. Wanting to purge the natural gas, they figured they'd burn it and let it go out in a few days... though almost 50 years later, it's still burning.
Monticello Dam (California)
The Monticello Dam is home to an amazingly large drain hole, the largest in the world, in fact. This man-made hole exists to drain the overflow of water in order to prevent the dam from flooding, and this particular drain hole is known as the "bottomless pit." Not really bottomless, it measures in at 72 feet or 22 meters across and 700 feet or 213 meters in depth.
Great Blue Hole (Belize)
The great blue hole is the worlds largest naturally occurring, under-water sinkhole, just off the coast of Belize in the middle of the Lighthouse Reef. Measuring an impressive 410 feet or 125 meters deep and 985 feet or about 300 meters across, the great blue hole is considered to be a world-class destination among scuba diving enthusiasts who wish to get a good view of the local marine life.