Black Lake

Crno jezero is located at the exit of the Una River canyon, not far from the road between Bihać and Bosanska Krupa. It is a very interesting karst spring, set right in the canyon, and it flows almost imperceptibly into the Una.

Although the water is crystal clear, the lake appears dark because of its depth and constant shade, which is how it got its name. Beneath the calm surface lies a complex underground system — at a relatively shallow depth, an entrance opens into a vast cave gallery that descends further into the depths, creating a fascinating world of underwater channels and cavities.

The water temperature remains low and stable throughout the year, indicating that the spring comes from great depths and a long underground karst system, probably connected to Mount Grmeč. Because of this, unlike other springs in the area, Crno jezero remains clear and almost unchanged even after heavy rain.

This area is also rich in a specific underground fauna, including rare species adapted to life in darkness and cold water. Today, Crno jezero is a true natural rarity and a hidden gem of Krajina — a place that enchants with its silence, mysterious depth, and untouched beauty.