Large holes … South Africa.
Large holes or mine in Kimberley (Big Hole, Kimberley Mine) is a mine of open water and groundwater in Kimberley, South Africa, used to mine diamonds. The first diamonds found in the Erasmus Jacobs in Colesberg Kopje, later called the “Kimberley mine,” the estate Vooruitzigt belonging to the brothers De Beers in 1871. From 1871 to mid-July 1914, about 50,000 miners dug the hole with picks and shovels, while it is removed from around 2,720 pounds of diamonds. A big hole has an area of 17 hectares and is 463 meters wide. Was excavated to a depth of 240 meters
This is something natural developed .
That’s interesting, and so nice color of the water.