Number of amazing natural phenomena certainly may include periodically opened holes in different locations around the world.
1. Kimberlite pipe Mir (Mir diamond pipe), Yakutia, Russia (above).
Kimberlite pipe Mir - the quarry situated in the west of Yakutia in Mirny. The quarry has a depth of 525 meters and a diameter of 1.2 km. It is one of the world's largest open-cast mines.
2. Kimberlite pipe Big Hole, South Africa.
Big Hole - a huge inactive diamond mine in Kimberley (South Africa). It is believed that this is the largest quarry, developed by people without the use of technology. Currently, it is the main attraction of the city of Kimberley.
3. Kennecott Bingham Canyon Mine, Utah (USA).
The largest operating mine in the world now - a copper development began in 1863. About a kilometer deep and three and a half kilometers wide.
Diavik is probably one of the youngest (by development) diamond kimberlite pipes. It was first prospected in 1992, the infrastructure was created by 2001, and diamond production started in January 2003. Presumably the mine will last from 16 to 22 years.
World-famous Great Blue Hole - the main attraction of the beautiful, environmentally perfect Belize (formerly British Honduras) - the state in Central America, on the Yucatan Peninsula.
6. Drain hole in Monticello Dam (US).
Large man-made hole is located in Northern California. But it is not just a hole. Drain Hole in Monticello Dam reservoir is the largest spillway in the world! It was built about 55 years ago.
7. Karst collapse in Guatemala.
Giant crater’s depth is 150 meters and its diameter - 20 meters. Due to underground water and rainfall. Its collapse caused the deaths of several people and destroyed a dozen homes. According to local residents, since the beginning of February in the area of future tragedy they felt shifts of the soil and heard the muffled roar out of the ground.