So, what is Karst?
Karst is a landscape formed from the dissolution of soluble rocks such as limestone, dolomite and gypsum, and its features include sinkholes and caves.
And nowhere better is Karst shown than in northern Croatia and Slovenia, an absolutely beautiful part of the world. I took the photo below in Krka National Park in Croatia, with its 72.5km long river, 7 waterfalls and numerous islands, lakes and caves. I don’t think I’ve ever swum in water so cold. But it was beautifully clear, clear enough that you could see (and catch your legs on if you weren’t careful) the travertine just under the surface.
Krka National Park’s website has some stunning photos of this area, and is in Croatian and English. http://www.npkrka.hr/