River Čabranka is a 17- kilometer long river, left tributary to river Kupa and a natural border between Croatia and Slovenia. It's source is just 20-30 minutes of walking from the centre of Čabar. The water emerges from the hill on Croatian side of the canyon, almost as a strong waterfall and rushes down to meet stream Belica coming from Slovenian side. Interestingly, despite being some 35 kilometers from the Adriatic coast, this water ends in the Black Sea which is ~1000 km away. There is a small rest-stop beside the source and a nice red wooden bridge just above it. This is Checkpoint No. 17 of Goranski planinarski put, at 550 m.a.s.l. The trail goes further into the forest, along the canyon, towards Prezid.