The valley of Velika Paklenica is 14.5 km long. Its watertight river bed, stretching from the spring down to its confluence with Brezimenjača, allows the river to retain water throughout the year. In a stretch of some 3 km in length, from Anića Kuk down to Marasovići, it displays very distinct canyon features – it is narrow (a few dozen metres in width) and deep (up to 400 m). At some points there are collapsed rocks and boulders which partially block the canyon, creating rapids and small waterfalls.
Velika Paklenica canyon is an area of exceptional geomorphological value, considered to be the most attractive Croatian climbing site, known to climbers all over Europe and beyond.