Neptune’s Grotto: 654 Steps Overlooking the Sea to an Underground Lake

What a sight! 654 steps carved into the rock overlooking the sea lead you straight into a fairy-tale underground world. The Grotta di Nettuno, on the Capo Caccia promontory, is one of the largest sea caves in Italy. The calling card is Lake Lamarmora, a saltwater lake 120 meters long that you encounter right after the entrance. Stalactites, stalagmites, and limestone columns accompany you along a route of about one kilometer, through majestic halls and narrow passages. The atmosphere is damp, silent, almost suspended in time. Arriving by sea adds a touch of adventure, but the Escala del Cabirol staircase is an experience you won’t forget: 654 steps descending along the cliff, with the blue sea watching you from every side. A place that leaves you speechless, literally.

What a sight! 654 steps carved into the rock overlooking the sea lead you straight into a fairy-tale underground world. The Grotta di Nettuno, on the Capo Caccia promontory, is one of the largest sea caves in Italy. The calling card is Lake Lamarmora, a saltwater lake 120 meters long that you encounter right after the entrance. Stalactites, stalagmites, and limestone columns accompany you along a route of about one kilometer, through majestic halls and narrow passages. The atmosphere is damp, silent, almost suspended in time. Arriving by sea adds a touch of adventure, but the Escala del Cabirol staircase is an experience you won’t forget: 654 steps descending along the cliff, with the blue sea watching you from every side. A place that leaves you speechless, literally.

The Neptune’s Grotto formed about 2 million years ago, but its official discovery dates back to the 18th century by an Alghero fisherman named Ferrandino. However, the Romans may have already frequented it, given the nearby Portus Nymphaeus at Porto Conte. In 1829, King Charles Albert of Savoy visited, accompanied by Alberto La Marmora; he returned in 1841 with his son Victor Emmanuel (future king of Italy) and in 1843 with the English traveler John Warre Tyndale, who described it in his work. Until 1954, access was only by sea. Then the spectacular Escala del Cabirol was built, a 654-step zigzag staircase down the cliff face of Capo Caccia, attributed to architect Antoni Simon Mossa. In 1999, the area became part of the Porto Conte Regional Natural Park, and in 2002 it became a Marine Protected Area.

The Neptune’s Grotto formed about 2 million years ago, but its official discovery dates back to the 18th century by an Alghero fisherman named Ferrandino. However, the Romans may have already frequented it, given the nearby Portus Nymphaeus at Porto Conte. In 1829, King Charles Albert of Savoy visited, accompanied by Alberto La Marmora; he returned in 1841 with his son Victor Emmanuel (future king of Italy) and in 1843 with the English traveler John Warre Tyndale, who described it in his work. Until 1954, access was only by sea. Then the spectacular Escala del Cabirol was built, a 654-step zigzag staircase down the cliff face of Capo Caccia, attributed to architect Antoni Simon Mossa. In 1999, the area became part of the Porto Conte Regional Natural Park, and in 2002 it became a Marine Protected Area.

Upon entering, the first thing you encounter is Lago Lamarmora: 120 meters long, 9 meters deep, with a water level matching that of the sea. Rising from its center is the Acquasantiera, a stalagmite that collects fresh water. A bit further on, the Hall of Ruins shows signs of damage caused by 19th-century visitors. The Hall of the Palace is the beating heart: limestone columns up to 9 meters high, a ceiling reaching 18 meters, and a submerged formation called the Christmas Tree. The Smith Hall (or Organ Hall) houses the Great Organ, a column 50 meters wide, while the Hall of Lace and Embroidery amazes with its delicate concretions. The tour ends at the Music Tribune, a balcony where an orchestra once played. Don’t miss the Pebble Beach, a small cove of white sand. The guided tour lasts about 30 minutes.

Upon entering, the first thing you encounter is Lago Lamarmora: 120 meters long, 9 meters deep, with a water level matching that of the sea. Rising from its center is the Acquasantiera, a stalagmite that collects fresh water. A bit further on, the Hall of Ruins shows signs of damage caused by 19th-century visitors. The Hall of the Palace is the beating heart: limestone columns up to 9 meters high, a ceiling reaching 18 meters, and a submerged formation called the Christmas Tree. The Smith Hall (or Organ Hall) houses the Great Organ, a column 50 meters wide, while the Hall of Lace and Embroidery amazes with its delicate concretions. The tour ends at the Music Tribune, a balcony where an orchestra once played. Don’t miss the Pebble Beach, a small cove of white sand. The guided tour lasts about 30 minutes.

If you arrive by land, you’ll be greeted by the Escala del Cabirol (Roe Deer Staircase), 654 steps carved into the cliff face of Capo Caccia, a 119-meter drop. Built in 1954 by architect Antoni Simon Mossa, it’s considered one of the most daring staircases in the world. Descending is thrilling: the sea is right beside you, rocks surround you, and every turn offers a breathtaking view. But be warned: climbing back up is tough! Bring water and wear non-slip shoes. During summer, avoid the midday hours. The staircase is the only pedestrian access to the cave, and it’s an experience worth having at least once: you’ll feel like a roe deer, suspended between sky and sea. At the end, the cave entrance welcomes you like a well-deserved reward.

If you arrive by land, you’ll be greeted by the Escala del Cabirol (Roe Deer Staircase), 654 steps carved into the cliff face of Capo Caccia, a 119-meter drop. Built in 1954 by architect Antoni Simon Mossa, it’s considered one of the most daring staircases in the world. Descending is thrilling: the sea is right beside you, rocks surround you, and every turn offers a breathtaking view. But be warned: climbing back up is tough! Bring water and wear non-slip shoes. During summer, avoid the midday hours. The staircase is the only pedestrian access to the cave, and it’s an experience worth having at least once: you’ll feel like a roe deer, suspended between sky and sea. At the end, the cave entrance welcomes you like a well-deserved reward.

Three good reasons to put the Grotta di Nettuno at the top of your list. First: the Lago Lamarmora is one of the largest underground saltwater lakes in Europe, and seeing it up close is a unique experience. Second: the limestone formations are spectacular, from the Sala della Reggia with its enormous columns to the Grande Organo that looks like a monumental instrument. Third: the access itself is an adventure, whether you choose the cliffside staircase or arrive by boat from the port of Alghero. Additionally, the cave was the set for the film L’isola degli uomini pesce (1978), a small piece of cinema history. The guided tour is short but rich, and the guide shares interesting anecdotes about discoveries and famous figures who have passed through here.

Three good reasons to put the Grotta di Nettuno at the top of your list. First: the Lago Lamarmora is one of the largest underground saltwater lakes in Europe, and seeing it up close is a unique experience. Second: the limestone formations are spectacular, from the Sala della Reggia with its enormous columns to the Grande Organo that looks like a monumental instrument. Third: the access itself is an adventure, whether you choose the cliffside staircase or arrive by boat from the port of Alghero. Additionally, the cave was the set for the film L’isola degli uomini pesce (1978), a small piece of cinema history. The guided tour is short but rich, and the guide shares interesting anecdotes about discoveries and famous figures who have passed through here.

The best time? Spring and autumn, when temperatures are mild and the sea is not too rough. If you come in summer, brace for heat: the staircase is exposed to the sun, and going down and up with 30°C can be tough. Better early morning or late afternoon. The cave is open all year (except Wednesdays and Christmas), but boat excursions depend on sea conditions. In winter, rainy or rough sea days can close the sea access, and the stairs become slippery. A tip: check the forecast and call the ticket office before you go. The artificial lighting in the cave is always on, so don’t worry about light: inside it’s a world of its own, regardless of the time of day.

The best time? Spring and autumn, when temperatures are mild and the sea is not too rough. If you come in summer, brace for heat: the staircase is exposed to the sun, and going down and up with 30°C can be tough. Better early morning or late afternoon. The cave is open all year (except Wednesdays and Christmas), but boat excursions depend on sea conditions. In winter, rainy or rough sea days can close the sea access, and the stairs become slippery. A tip: check the forecast and call the ticket office before you go. The artificial lighting in the cave is always on, so don’t worry about light: inside it’s a world of its own, regardless of the time of day.

Once you’ve satisfied your craving for caves, the Capo Caccia promontory offers other wonders. Nearby, the Grotta Verde (also known as Altare Cave) is accessible only with a permit, but houses Neolithic graffiti and archaeological finds: a dive into Sardinian prehistory. If you love the sea, the Capo Caccia e Isola Piana Marine Protected Area is perfect for snorkeling and diving; here you’ll also find Nereo Cave, the largest underwater sea cave in the Mediterranean, but only for experienced divers. A few kilometers away, Porto Conte offers quiet beaches and a nature reserve for birdwatching. And then there’s Alghero, with its Catalan old town, seafood restaurants, and coves: a perfect weekend combining nature and culture.

Once you’ve satisfied your craving for caves, the Capo Caccia promontory offers other wonders. Nearby, the Grotta Verde (also known as Altare Cave) is accessible only with a permit, but houses Neolithic graffiti and archaeological finds: a dive into Sardinian prehistory. If you love the sea, the Capo Caccia e Isola Piana Marine Protected Area is perfect for snorkeling and diving; here you’ll also find Nereo Cave, the largest underwater sea cave in the Mediterranean, but only for experienced divers. A few kilometers away, Porto Conte offers quiet beaches and a nature reserve for birdwatching. And then there’s Alghero, with its Catalan old town, seafood restaurants, and coves: a perfect weekend combining nature and culture.