A spring cave in the limestone east of Grazalema, where an underground river bursts out of the rock into a pool of cold blue-green water. The spot is a popular summer swimming hole — chilly, deep, and dramatic, with the cave mouth black against the pale cliffs.
Officially the cave itself is closed to all but permitted cavers (it stretches several kilometres back), but the pool is open. Park at Estación de Benaoján on the Algeciras–Bobadilla railway line and walk twenty minutes along the river. Quiet on weekdays, packed on summer Sundays.