The Earth has succumbed to many drastic changes in its appearance over millions of years. Some holes on the Earth were made by man. Other surface disturbances occurred from impacts from masses, such as meteors, or disruptions created by the Earth. The holes resulting from such changes have left behind remarkable landscapes throughout the world.
Blue Holes
Blue holes are named for their blue coloration on the surface of the hole. The Belize Blue Hole measures 1,000 feet across and reaches a depth of 400 feet. This blue hole was formed during an ice age when the hole was once a cave system. The Belize Blue Hole developed after the ice melted, raising sea levels and submerging the caves. Dean's Blue Hole is touted as the deepest, reaching depths of 663 feet. After reaching a depth of 75 feet, Deans Blue Hole in the Bahamas widens to 240 feet with a cascading wall of sand that topples over the edge of the shaft.
Man-Made Holes
Once a flat-topped hill, the Kimberley Mine, or Big Hole, in South Africa became the largest excavation completed by hand digging. Workers dug this hole with picks and shovels, digging to depths of more than 700 feet. More than 22 million tons of earth were extracted from the Big Hole in search of diamonds. Kennecott's Bingham Canyon Mine in Utah is not only one of the largest copper mine's in the world, but also the largest man-made excavation hole. The mine is more than 0.75 miles deep, has an opening 2.5 miles wide and can be seen from space.
Craters
The Vredefort Dome in South Africa is an astrobleme. An astrobleme is the remains of a large meteorite impact. Vredefort Dome is the largest known crater, with a radius of more than 118 miles. This crater also is the oldest known crater, dating back 2,023 million years, according to the United Nations Educational, Scientific and Cultural Organization. The second-largest crater in the world is Sudbury Basin in Canada. The Sudbury measures more than 30 miles long with a width of more than 18 miles. The original size of the crater was estimated at more than 155 miles in diameter, but due to geological processes, the crater is only a fraction of what it used to be.
Sinkholes
Throughout China are several Tiankeng, or heavenly pits. These pits are sinkholes that occur naturally when repeat cave-ins on the surface of land occurs. Nearly 50 of these Tiankeng sinkholes exist in China, with the Xiaozhai Tiankeng being the largest. This sinkhole is more than 2,100 feet deep. In Jaua-Sarisarinama National Park in Venezuela, exists a mountainous region known as the Sarisarinama tepui. The mesa tops of the tepuis, or table top mountains, rise up to 4,000 feet, with sinkholes reaching more than 1,000 feet.
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