At the entry of the Slunjčica into the Korana river, there exists a natural travertine barrier consisting of a large accumulated lime deposit. Rastoke and the travertine barrier itself used to be separated into the "Upper" and the "Lower Rastoke" (Croatian ""Gornje i donje Rastoke""). The lower part of Rastoke consists of 23 waterfalls, which fall about 10 to 20 meters deep into the Korana. The barrier as a whole consists of various small waterfalls, rapids and basins. The most famous waterfalls are "Buk" (English "waterfall"), "Hrvoje" and "Vilina kosa" (English "fairy hair").