The Derweze area is rich in natural gas. While drilling in 1971 geologists accidentally found an underground cavern filled with natural gas. The ground beneath the drilling rig collapsed, leaving a large hole with a diameter of about 50-100 meters. To avoid poisonous gas discharge, it was decided to burn the gas.The Locals have named the cavern The Door to Hell. It sure scares me.

The Monticello Dam Powerplant was built at the dam in 1983 and has three generators. The electrical power is sent mostly to the North Bay area of San Francisco.The dam is noted for its classic, uncontrolled spillway with a rate of 48,400 cubic feet per second (1370 m³/s) and a diameter at the lip of 87 ft (27 m).

It’s an absolute beast and holds the title of largest open diamond mine in the world. at 525 metres deep with a top diameter of 1200 metres there’s even a no-fly zone above the hole due to a few helicopters being sucked in. It is now abandoned but while it was still operational, it would take two hours for trucks to drive to the bottom.

On February 23rd 2007, a 330 foot wide sinkhole in Guatemala swallowed a dozen homes, killing 2 and causing thousands to be evacuated. Authorities believe that the sinkhole was caused by rains and underground sewage flow.

The Kimberley Diamond Mine (also known as the Big Hole) holds the (disputed) title of being the largest hand-dug hole in the world. From 1866 to 1914 50,000 miners dug the hole with picks and shovels, yielding 2,722 kg of diamonds. Attempts are being made to have it registered as a world heritage site.

The Diavik Mine is a mine in the Northwest territories of Canada. The mine (opened in 2003) produces 8 million carats or about 1,600 kg (3,500 lb) of diamonds every year.

The Great Blue Hole is a large underwater sinkhole off the coast of Belize on a small atoll 100 kilometres from the mainland. The hole is over 300 metres across and 125 metres deep. It was formed as a limestone cave system during the last glacial period when sea levels were much lower. As the ocean began to rise again, the caves flooded, and the roof collapsed. A World Heritage site of the United Nations Educational, Scientific and Cultural Organization (UNESCO).

This is supposedly the largest man-made excavation on Earth. Extraction began in 1863 and still continues today. The pit constantly increases in size. In its current state the hole is 1.2 km deep and 4 km wide.

As its name suggests, this big hole in the ground was created by a catastrophic meteorite impact roughly 50,000 years ago. The object that created this was roughly 50 meters wide and was travelling anywhere between the speeds of 28,000 and 45,000 mph. Rumour has it the owners of this site now want to turn it into an amusement park. Interesting.

The Udachnaya Pipe is an open cast diamond mine in Russia. The owners of the mine plan to cease its operations in 2010 - in favor of underground mining. The mine was discovered in 1955 and is over 600 meters deep.

Eroded by the Colorado River, the Canyon is immense, averaging 4,000 feet deep for its entire 277 miles. It is 6,000 feet deep at its deepest point and 15 miles at its widest. The land is semi-arid and consists of raised plateaus and structural basins typical of the southwestern United States. Drainage systems have cut deeply through the rock, forming numerous steep-walled canyons.

The Atacama desert is one of the dryiest and inhospitable places in the world, but it also contain the biggest and purest copper deposits. This open air mine is the biggest in the world at 850meters deep. The trucks you see are quite huge (there is a normal car on the picture if can you find it ?), it is therefore difficult to understand the true scale of this mine.