Pensando en números negativos

https://www.youtube.com/watch?v=TiJgMTDd45c#t=100

Publicado el 2/01/2013

FREE FALL: World champion Free Diver Guillaume Nery special dive at Dean’s Blue Hole, the deepest blue hole in the world (202 Metres/663 Feet) filmed entirely on breath hold by the French champion Julie Gautier.
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Dean’s Blue Hole is the world’s deepest known blue hole with seawater. It plunges 202 metres (663 ft) in a bay west of Clarence Town on Long Island, Bahamas.

“Blue Hole” is a name which often is given to sinkholes filled with water, with the entrance below the water level. They can be formed in different karst processes, for example, by the rainwater soaking through fractures of limestone bedrock onto the watertable. Sea level here has changed: for example, during the glacial age during the Pleistocene epoch (ice age), some 15,000 years ago, sea level was considerably lower. The maximum depth of most other known blue holes and sinkholes is 110 metres (360 ft), which makes the 202 metres (663 ft) depth of Dean’s Blue Hole quite exceptional.

Dean’s Blue Hole is roughly circular at the surface, with a diameter ranging from 25 to 35 metres (82–115 ft). After descending 20 metres (66 ft), the hole widens considerably into a cavern with a diameter of 100 metres (330 ft).