Underground lake

Most naturally occurring underground lakes are found in areas of karst topography,[1][2] where limestone or other soluble rock has been weathered away, leaving a cave where water can flow and accumulate.

Below the surface of the Earth, the amount of pressure exerted on groundwater increases, causing it to be absorbed into the soil.

[2][7] In the saturated zone, pressure becomes the primary force driving the flow of water.

Naturally-occurring underground lakes can form in Karst areas, where the weathering of soluble rocks leaves behind caverns and other openings in the earth.

[2] Surface water can find its way underground through these openings[8] and pool up in larger caverns to form lakes.