1. Dean's Blue Hole
Where: Long Island, Bahamas
Located in a bay near Clarence Town on the Bahamas' Long Island, Dean's Blue Hole is 650 feet deep and is the dreaded challenge of every professional deep-sea diver. Legend has it that the hole was dug by the devil that drags people in it and kills them.
2. Kennecott Copper Mine
Where: Salt Lake City, Utah
Also known as the Bingham Canyon Mine, the mine was named a National Historic Landmark in 1966. It is a huge 2.5 mile-wide pit located in the Oquirrh Mountains outside Salt Lake City, and is currently owned by the Rio Tinto Group, an international mining and exploration company headquartered in the United Kingdom.
3. Chand Baori
Where: Abhaneri, Rajasthan
Located opposite Harshat Mata temple in Rajasthan, India, Chand Baori (baori means a steepwell) extends approximately 100 ft into the ground making it one of the deepest and largest stepwells in India. It was constructed in 800 AD and consists of 3,500 narrow steps and over 13 stories. Movies like 'The Fall' and 'The Dark Knight Rises' have been shot here.
4. Kimberley Mine
Where: Kimberley, South Africa
This location was once home to more than 6,000 pounds of diamonds. Also known as the 'Big Hole' it is also the largest hand-dug excavation in the world to date.
5. Door To Hell
Where: Derweze, Turkmenistan
A massive molten cavity known as the Darvaza crater nicknamed the 'door to hell' is a continuous burning hole located in Derweze, Turkmenistan. The crater, which is 69 metres wide and 30 metres deep has been burning for the last 40 years. George Kourounis, a Canadian explorer, became the first person known to have ventured into the pit last year. His aim was to explore the hole and to check if there were any signs of life.
6. The Kola Superdeep Borehole
Where: Pechengsky District, Russia
This hole is the result of a scientific drilling project of the Soviet Union in the Pechengsky District, on the Kola Peninsula. The project has dug the deepest artificial point on Earth, measuring a crazy 40,230 ft!
7. The Great Blue Hole
This hole is a UNESCO World Heritage Site and is also a popular recreational scuba diving spot. The site was made famous by Jacques Cousteau, who declared it one of the top ten scuba diving sites in the world. The Great Blue Hole is nearly 1,000 feet wide and more than 400 feet deep.
8. The Sawmill Sink
Where: Abaco Island, Bahamas
This blue hole lies in the interior of Abaco Island in the northern Bahamas. The hole is the location for the amazing find of the remains of a 2,500-year-old giant tortoise shell. The sinkhole measures 55 feet (17 meters) across and 110 feet (33.5 meters) deep.
9. Crveno Jezero
Where: Imotski, Croatia
Crveno Jezero is the third largest sinkhole in the world. The sinkhole is named after the reddish-brown color of the surrounding cliffs, coloured by iron oxides.
10. The Devil's Sinkhole
Where: Edwards County, Texas
The Devil's Sinkhole is 350 ft deep and is home to millions of Mexican free-tailed bats. It's a scary sight when millions of bats fly from the entrance to the sinkhole.