A calanque 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 traditional local language) in the Bouches-du-Rhône department of Southern France. The range extends for 20 km (12 mi) in length and four kilometres (2.5 mi) in width along the coast between Marseille and Cassis, culminating in Mont Puget (565 m or 1,854 ft).
The calanques between Marseille and Cassis are popular amongst tourists and locals alike, offering several vantage points (such as the Corniche des Crêtes and Cap Canaille) allowing spectacular panoramas. A great number of hikers frequent the area, following numerous pre-marked trails.