Piatra Craiului, or just Crai, is a limestone mountain range to the southwest of the Eastern Carpathians, being part of the Southern Carpathians, located in their northeastern part.
The geology and geomorphology of the massif differs from that of the surrounding mountains, which consist almost entirely of crystalline rocks, the “Crai” being a sharp and steep “blade” composed of metamorphic rocks, mainly Jurassic limestone, approximately 24 to 26 km long, with a southwest-northeast orientation, and 6 to 8 km wide. Its famous vertical walls, 400-650 m high, are the result of the horizontally layered limestone.
The highest point of the massif is La Om Peak, also known as Piscul Baciului, 2,238 m. There are many peaks over 2,000 meters: Padina Popii Peak (2,018 m), Ascutit Peak (2,150 m), Timbalul Mare Peak (2,177 m), Varful dintre Timbale Peak (2,170 m), Sbirii Peak (2,220 m), Caldarea Ocolita Peak (2,202 m).
Dambovicioara Gorge and Dambovicioara Cave are the most important karst phenomena in Piatra Craiului Mountains. Zarnesti Gorge, Botorog Fountain, La Zaplaz, Cerdacul Stanciului, Stanciului Cave, the Devil’s Mill are other spectacular landforms in the northeastern part of the massif. Another karst formation to be mentioned is Marele Grohotis (The Great Scree), a 4 km-long unstable collection of rock fragments.
Piatra Craiului Nature Reserve was established in 1938, covering more than 1,200 hectares of the massif.