The karstic environment
In geological terms, the entire western part of the Alghero area plays host to an immense profusion of limestone rocks that are several hundred metres thick.
The sedimentary deposits, which emerged definitively around 70 million years ago, have been subject ever since then to the incessant erosive forces of water and wind, as well as to the effects of waves, salt water and rain. The result is a collection of various cave systems, each different from the next, with concretions of stalactites, stalagmites and columns.
La Grotta di Nettuno (Neptune’s Cave)
The most famous and most visited cave in and around Alghero is Neptune’s Cave, which is one of the most spectacular works that the infiltration of water has succeeded in creating over the course of millions of years.
This imposing, 2500m-long cave dates from the Cretaceous period and contains traces of the geological history of the entire limestone system of Capo Caccia.
The section that can be visited constitutes a small but significant part.
The cave can be reached either by sea (leaving from the port, from Dragunara beach or from our hotel’s jetty) or by land, making your way down the challenging Escala del Cabirol, starting from Capo Caccia’s large square.
The cave follows a tortuous, complex path, with expansive chambers, tunnels, numerous lakes and important concretions of stalactites and stalagmites.
La Grotta Verde (Green Cave)
Another well-known cave is the Grotta Verde or Green Cave. Its mouth is on the eastern side of Capo Caccia, where there is a large, high opening to the sea.
The cavity is funnel-shaped and slopes down until reaching sea level with two internal lakes. The cave continues onward under the surface into large spaces that have never been fully explored.