Karst landscape, satellite image. Karst topography is a geological formation shaped by the dissolution of layers of soluble rock such as limestone. Mature karst landscapes, where more bedrock has been removed than remains, may result in karst tower landscapes. Beneath the surface, complex underground drainage systems (such as karst aquifers) and extensive caves and cavern systems may form. This is Guangxi Province in southeast China. The area shown here is 28 by 31.5 kilometres. The image was acquired on 3 December 2013 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite.