The stream Poreznica runs through the gully Zakojška grapa, across the steep terrain to the western side of Porezen, the highest mountain in the Cerkno region. On its path to the valley, the stream has created numerous small and large waterfalls, rapids and pools. It runs through the forest and preserved wilderness, since this area has been uninhabited for many years. However, in the past this part of Porezen was settled, mills and sawmills were located on the stream until the great flood in 1926.
An interesting hydrological element of natural heritage is the spring Zaganjalka under the Cerkno hill, in the gully Volkova grapa near the Zakrog homestead. Zaganjalka is reached by descent from the chapel at Lajše. It represents an interesting Karst phenomenon, characterised by the changing water flow. At normal flow, it takes seven minutes for the spring to almost dry up and the water to come gushing again from the depths.
In the forest between the villages Gorje and Jesenica an interesting, special tree has grown. It is a twist of nature, two joined beech trees - Siamese twins. Only the locals know about them. The Twin Tree is located next to the forest path.
Fun fact: The cave Aragonitna Ravenska jama
This cave is a natural monument. It combines 352 metres of tunnels on three levels. It is famous for rich aragonite ornaments. Fragile, snow-white aragonite crystal covers are formed as stalactites and stalagmites, sinters and needle like structures of different shapes and sizes.