Rák Lake is located 2 km North of Porumbenii Mari at an altitude of 600 m. It formed due to a landslide at the end of the glacial period. The relief consists of Neogene sedimentary rocks, Sarmatian clay marble and sandstone.
The circumference of the lake is 800 m, its length 250 m, width 150 m, the maximum depth is 7 m and the surface is 28.000 sq m, 10 ha with the adjacent land.
The area is a natural reserve protected by the Law 5/2000.
The lake and its surroundings are home to many rare species of plant, including the common bladderwort (Utricularia vulgaris), a carnivorous plant, which feeds on small aquatic insects, crabs and mosquito larvae.