karst terrain

The Taam Ja' blue hole is at least 420 meters below sea level and may be connected to a system of hidden caves and tunnels.

The Egyptian pyramid-like shape of Guizhou's mountains is the result of natural erosion over a period of hundreds of millions of years.

In an article published on Circle of Blue's environmental page, Chris Groves explained how the karst caves and terrain kept a clue about the earth's climate.