The final day of the Huck Finn Istria Multisport trip was spent walking in the Plitvice Lakes National Park. We went there via a back road from Rijeka, through vast woods, and saw an instance of the Yugoslav Wars, a house with bullet marks on it from when the Serbians (or was it Bosnians) had attacked Croatia.
The park, which is near the border with Bosnia, is on the the UNESCO World Heritage register.
There’s a series of lakes and attractive cascades, and the water is crystal clear. It can get pretty busy near the entrance. For some unknown reason, the park is particularly popular with visitors from South Korea. Everyone seems to obey the rules of the park which do not allow off-track walking.
The sedimentation processes which created the lakes are described in Wikipedia.