Plitvice Lakes National Park contains a series of beautiful lakes, caves and waterfalls. These have been formed by processes typical of karst landscapes such as the deposition of travertine barriers, creating natural dams. These geological processes continue today.
The Plitvice Lakes National Park was granted UNESCO World Heritage status in 1979. The lakes are renowned for their distinctive colours, ranging from azure to green, grey or blue. The colours change constantly depending on the quantity of minerals or organisms in the water and the angle of sunlight.
There are 16 interlinked lakes between Mala Kapela Mountain and Pljesevica Mountain. The lake system is divided into the upper and lower lakes: the upper lakes lie in a dolomite valley and are surrounded by thick forests and interlinked by numerous waterfalls; the lower lakes, smaller and shallower, lie on the limestone bedrock and are surrounded only by sparse underbrush. The upper lakes are separated by dolomite barriers, which grow with the formation of travertine, forming thus travertine barriers. Travertine is mostly formed on the spots where water falls from an elevation, by the incrustation of algae and moss with calcium carbonate. The lower lakes were formed by crumbling and caving-in of the vaults above subterranean cavities through which water of the upper lakes disappeared.