Underground lake - online puzzles

Underground lake

An underground lake or subterranean lake is a lake underneath the surface of the Earth. Most naturally occurring underground lakes are found in areas of karst topography, where limestone or other soluble rock has been weathered away, leaving a cave where water can flow and accumulate.

Natural underground lakes are an uncommon hydrogeological feature. More often, groundwater gathers in formations such as aquifers or springs.

The largest subterranean lake in the world is in Dragon's Breath Cave in Namibia, with an area of almost 2 hectares (5 acres); the second largest is The Lost Sea, located inside Craighead Caverns in Tennessee, United States, with an area of 1.8 hectares (4.4 acres)

Bielsko Cave puzzle online from photoWater In Cave puzzle online from photo