At the foot of the Capo Caccia cliff, the sea hides a cathedral: Neptune's Grotto, with its inner salt lake, twenty-metre columns and concretions dripping for a hundred thousand years. You arrive by boat from Alghero — sea permitting — or down the Escala del Cabirol, 654 steps cut into the cliff face in 1954, a vertiginous work that is half the adventure.
Visits are guided, and raking light on the inner water makes reflections from an alien planet.
Our tip: with rough sea the boat cannot dock: if the weather wobbles, choose the stairway (remembering you must climb back up). An afternoon ticket finds the cliff golden on your way out.
