A calanque (French: [kalɑ̃k], "inlet"; Corsican: calanca, pl. calanche; Occitan: calanca, pl. calancas) is a narrow, steep-walled inlet that is developed in limestone, dolomite, or other carbonate strata and found along the Mediterranean coast. A calanque is a steep-sided valley formed within karstic regions either by fluvial erosion or the collapse of the roof of a cave that has been subsequently partially submerged by a rise in sea level.
The best known examples of this formation can be found in the Massif des Calanques (Massís dei calancas in Occitan, the historic local language) in the Bouches-du-Rhône département of France. This range extends for 20 km in length and 4 km in width along the coast between Marseille and Cassis, culminating in Marseilleveyre (432 m) and Mont Puget (565 m). Similar calanques can also be found on the French riviera near Estérel and on the island of Corsica (see Calanques de Piana). The highest point along the calanques are located at Mount Puget (565 meters)and in the mountains of Marseilleveyre (432 meters). Similarities are seen between calanques, and rias, the river mouths formed along the coast of Brittany in Northern France.