🌋 Nature & views

Neptune's Grotto

📍 Alghero, Sardinia · 84/100

Discovered by local fishermen in the 18th century, Neptune's Grotto (known in Catalan as Cova de Neptú) takes its name from the Roman god of the sea. The cave entrance sits just one metre above sea level at the base of the 110-metre-high Capo Caccia cliffs, near the town of Alghero in Sardinia. While the entire karst system is estimated to stretch for 4 kilometres, approximately 300 metres are open to the public. Historically, the grotto served as a habitat for the Mediterranean monk seal, a species that has since become extinct in this area.

What to see

The public section of the cave consists of lit pathways winding through extensive stalactite and stalagmite formations. These passages eventually lead to a 120-metre-long saltwater lake that sits entirely at sea level. The subterranean landscape was prominent enough to be used for cinema: over two months in the summer of 1978, the cave was transformed into a massive set for Sergio Martino's science fiction film Island of the Fishmen (1979), starring Barbara Bach and Claudio Cassinelli. The surrounding cliff face holds other natural cavities, including the Green Grotto, which is closed to tourists, and the Grotta di Ricami, which can only be reached from the water. Beneath the surface lies a network of marine caves, most notably the Nereo Cave, which attracts thousands of scuba divers every year.

Visiting

Because the entrance is so close to the water, the grotto can only be accessed when the sea is calm. Visitors proceed single-file along a lit pathway during a one-hour guided tour, with commentary provided in both Italian and English. The site sees heavy footfall; during the peak tourist month of August, the cave can hold around 200 people at any given time. Access to the entrance is available either by a short boat trip from the port of Alghero—running hourly in summer and less frequently in spring and autumn—or on foot via the escala del cabirol (goat's steps). Cut directly into the cliff in 1954, this 654-step stairway descends from the clifftop car park straight down to the water's edge.

Our editors' tip

Always check the local sea conditions before heading to Capo Caccia. Because the cave entrance is only a metre above the water, access is strictly prohibited when the waves are rough.

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