The Neptune Caves

Within the limestone mass of Capo Caccia, on the side most battered by the sea, is one of the most unforgettable geological marvels to amaze those who have a chance to visit it. These are the Neptune Caves in Alghero which attract more than 150,000 visitors a year from all over the world; they are drawn by the wonderful spectacle of curious geological formations and the clear waters of the internal lake, as well as by the caves' historical importance. The caves are large, extending for a total of 2,500 meters, with a complex array of caverns, wide passages, small, clear lakes, deep wells and narrow tunnels. A series of natural formations within makes these caves some of the most interesting and important in the Mediterranean basin. Geologicall, the Cape Caccia promontory is made of limestone rock formed during the Cretaceous period, between 135 and 65 million years ago.

A little history…

In 1954 the Escala del Cabirol were cut into the rock face, finally enabling visitors to reach the caves by land. Shortly after this the caves were illuminated and then opened to the public. Previous to this, for more than 150 years, access to the caves had been limited to boats in the summer season only and even then trips had to be called off if the sea was rough. The first mention of the Neptune Caves dates back to the end of the eighteenth century; since then numerous writers have extolled the beauties of the caves, considering them to be superior to other famous caves in Europe. In the early part of the nineteenth century, the growing fame of the Neptune Caves began to attract eminent visitors, including several princes and kings. Charles Albert of Savoy came three times, first as Prince of Carignano in 1829 and then as the King of Sardinia in 1841 and 1843. On the walls of the palace on the sandy shore at the end of Lake Lamarmora, visitors today can see two marble stones commemorating the first two visits by Charles Albert. Other well-known visitors include the Englishman, Captain Henry Smith, who drew the first map of the early part of the caves, the Duke of Buckingham, the great Sardinia geographer Alberto Lamarmora, the Baron of Maltzan and Enrico Costa, the writer from Sassari who wrote a book about the caves. Plus many others, too numerous to mention here, who have published works enthusing about these extraordinary caves. Visits to the Neptune Caves in the last century were made in the summer season, with countless small boats leaving the port in Alghero. When they reached the caves, visitors disembarked in the broad entrance passage and then boarded another smaller boat to cross Lake Lamarmora. At the other end from the little ebach it was then possible to climb the slope to the upper caverns. In those days the light was provided by thousands of candles which were lit beforehand by sailors. It is not hard to imagine the enchanting spectacle for visitors as a host of tiny quivering flames threw shadows onto the walls and cast their reflections into the clear waters of the lake.

How to Reach the Caves

From the town of Alghero, the Neptune caves can be reached in two different ways. By sea, leaving from the town port, the journey by boat takes about an hour. Visitors can admire the scenery of the Coral Riviera as the boat passes close to the Cape Galera and Punta Giglio cliffs and then rounds the tip of Capo Caccia to arrive right at the entrance to the caves which lie at the foot of a towering cliff - an impressive sight set against the backdrop of the small island of Foradada. Overland by car, the caves are 24 km from Alghero. As the road curves around Capo Caccia one of the best views in Sardinia comes into sight, taking in the bay of Porto Conte, the town of Alghero and reaching as far south as the Bosa coast. From the Cape Caccia car park, visitors follow the path on the western side of the Cape, taking the Escale del Cabirol steps, which were built into the rock face in 1954 and which descend 110 meters to the entrance to the caves.

The Caves

Tourists can enter the great cavern at the beginning of the caves where steps have been cut and paths laid to enable people to walk around. The tour, 200 meters in length, winds around the shores of a salt water lake with extraordinarily clear waters and then climbs to a higher level where geological formations abound. The caves are managed by the Alghero Tourism Board which offers guided tours for visitors. Just past the wide entrance to the caves, where the boats ferrying passengers moor, is a vestibule where visitors can pause for a moment before starting the tour. From the entrance, visitors can see the salt water Lamarmora Lake which occupies a large part of the first cavern. On the wall of this cavern, for as far as the natural light from the outside filters in, a curious greenish-blue color is visible, caused by the tiny plant forms that manage to grow there. At the center of the vestibule, facing the shores of the lake, stands the Acquasantiera or holy water font, massive and curious two-meter high stalagmite often described by the countless poets, writers and geographers who visited the caves in the century. As a result of the constant dripping of water from above, little depressions have formed at the top of the stalagmite which collect small amounts of precious fresh water, probably the only source in this area for birds who next in the ravines of the Cape Caccia cliffs. Visitors begin the tour by taking the steps on the left side of the vestibule; at this point the natural light ends and the darkness, which has reigned here for thousands of years concealing the wonders of these caves, begins. After a brief descent the path comes to the Sala delle Rovine of Cavern of Ruins with its great stalactites, where a faint light from the outside is still visible, lending the walls a bluish color. From the Cavern of Ruins the path slopes down to the Lamarmora Lake, which is fairly shallow at this point, and follows the lake shore. The clear, still waters of this lake lend a particular charm to the atmosphere. On days when the sea is rough the contrast between the booming of the waves outside and the inner calm is particularly striking. The path then comes to Reggia or Palace where Nature has created the most breathtaking scene in the caves. On the right, in the center of the lake and reflected in its clear waters, stand great calcitic columns, nine meters high, that teach the rood, almost as if they were holding it up. Immediately after the columns, the roof is furrowed by a huge crack and rises to 18 meters in height, the highest point in the part open to tourists. The great wall at the end of the lake completes the scenario with tis great rock flows in the form of organ pipes, its calcitic concretions and a typical stalagmite formation called the Albero di Natale or Christmas Tree, which lies at the furthermost point. Lake Lamarmora ends here and, especially at low tide, a small sandy beach can be seen under the path. It used to be called the Spiaggia dei Ciottolini or Pebble Beache because it consisted of small pebbles only. Today, however, not a single pebble remains and they may all have been washed away by the waters of the lake. In the past, small boats used to ferry passengers across the lake to this point where they could disembark for a while to admire the splendid scenery before being taken back across the lake to the cave entrance. The tranquility of the Palace is barely disturbed by the faint lapping of the waters of the lake while, looking back towards the entrance, the strange bluish light that filters in from outside in from outside is still faintly visible, creating a peculiar play of colours on the walls. From the Palace, the path climbs away from the lake while, taking visitors to a higher level which offers views over the route just followed. The path then comes to Sala Smith or Smith Cavern, named after an Englishman who was one of the first explorers of the cave in the early nineteenth century. The Smith Cavern is not actually a separate cavern but a continuation of the great cavern. At the center of this cavern stand the Grande Organo or Great Organ, a massive column with rock flows similar to organ pipes. Standing 11 meters high, 12 meters wide and 4 meters deep, it is the largest formation in the whole of the Neptune Caves. Many thousands of years have passed since the first drop of water fell, starting the long slow process of creating this gigantic column. Immediately after this, the path takes visitors to the Cupola or Dome, a curious stalagmite formation whose perfectly smooth walls, joined to the roof by a column, call to mind the dome of a cathedral. Nearby the floor is pitted with huge stalagmite basins which today are dry but which were once filled with water and must have made an impressive sight as the water gushed down towards Lake Lamarmore. Other columns and stalagmites adorn this cavern. Before the Dome, to the right, a path leads off to an area of the caves that has not been made safe for tourists and therefore is not included in the tour. Moving on, the path turns to the left and begins to rise again, along the wall opposite the Smith Cavern. Here the roof becomes lower and it is possible to get closer to a myriad of stalactites. Numerous small columns adorn this cavern, called the Sala delle Trine a dei Merletti or the Cavern of Lace, forming natural niches and arcades. The view opens out and the Great Organ is again visible from here, from a different angle. Finally the path comes to the Tribuna della Musica or the Music Platform, a natural balcony overlooking the Palace and the Lake. The name comes from the old tradition of setting up a small orchestra here for visits of particular importance, when visitors would hold dances on the lake shore below. The sound must have been extraordinary. From the Music Platform, there is an excellent view of the lake and a large part of the caves, making an interesting end to the tour. Visitors can then go back along the way they came to the entrance to the caves where they either board the boat or climb the Escala del Cabirol steps back to their cars.

Lake Lamarmora

Lake Lamarmore occupies the whole of the beginning of the caves and, at 100 meters longs, it is considered one of the largest salt water lakes in Europe. It is connected to the sea by a siphon under the entrance to the caves and its clear waters reflect the numerous limestone concretions that adorn the walls and the roof. When the sea is rough, huge waves come crashing violently into the caves, soaking the whole entrance, and the accompanying roar is deafening. Unfortunately in these conditions it is not possible to enter the caves or remain inside them and so visitors are unable to witness this tremendous, awe-inspiring sight. The connection to the sea means that the waters of the lake are not completely sill but ebb and flow slightly with the tide and small ripples are visible. The whole of the lake, to the far shore, can be crossed in a small flat-bottomed boat or a rowing boat. Before 1945 this was the only way to the caves. The initial stretch of the lake is the deepest part, reaching a depth of 8-9 meters where the siphon connects it to the sea. After 50 meters a small island creates a narrow stretch, after which the lake opens out to a breadth of 25 meters; at this point the waters become much shallower and it is possible to walk in them. After an array of rocks with stalagmite formations, the lake comes out to a breadth of 25 meters; at this point the waters become much shallower and it is possible to walk in them. After this the lake comes to an end at the sandy shore. One might think that nothing could live in these dark water but in fact certain life forms have adapted to these particular conditions and they do not seem to suffer from the presence of visitors. Easy to spot are crayfish, starfish, sea urchins, holothurias and the odd conger eel as well as various types of shellfish. Once in a while it was also possible to see monk seal but, sadly, today they have all disappeared from the lake in search of quieter sites elsewhere in the Mediterranean.

When the Sea was Higher

In the Palace a curious and perfectly straight black line can be seen running along the opposite wall of Lake Lamarmora, about four meters above the lake. During various glacial and interglacial periods that are a part of the history of the earth, the level of the sea underwent considerable variation, falling in colder periods and rising in warmer times, following the melting of the icepacks. About 125,000 years ago, during the Eutyrrhenian period, the level of the sea rose about 4 meters higher than it is today and remained stable at this height for a long period. The evidence of this rise can be seen in the black line which, many thousands of years later, is still visible on the rock face in the Palace. Outside the caves, on the cliffs of Cape Caccia, any trace of this line has been eroded by the action of the sea and the wind, but inside the Neptune Caves it has been preserved. The importance of the caves thus increases when one considers the amount of information they can give geologists and researchers as they attempt to build up a picture of the various climatic changes that occurred in the distant past in this part of the world. A closer look at the black line shows that it is not just visible on the walls that surround the lake but also on the columns, the rock flows and the larger stalactites, evidence that these concretions were already formed during the Eulyrrhenian period. To give an idea of their great age, the imposing column and the great rock flows stood here as we see them today long before man built the Pyramids, the walls of Babylon, the Sardinian nuraghe or the Coliseum in Rome. The greatest achievements of man do not bear comparison with the masterpieces of nature which come down to us perfectly preserved from distant ages. The black line, which can also be seen in other parts of the caves, shows that the lake was once much larger than it is today and a large part of the cavern at the entrance would have been submerged.

The Concretions

One of the great attractions of the Neptune Caves is its concretions, the limestone formations that decorate its walls and roof, created by nature over hundreds and thousands of years by the slow dripping of water. But how are these concretions formed? Rainwater, running down into cracks in the limestone, slowly dissolves the calcium carbonate in the rock, creating little cavities which grow larger with time, until they become the caves that we see today. The same water, now rich with the salts it has dissolved, trickles down to the floor of the cave and redeposits the calcium carbonate in the rock, giving rise to the formations that come in various different colors. At this point nature goes wild and creates stalacmites, columns, rock flows and small basins in many shapes and sizes. With a little imagination visitors can identify familiar objects and thus these underground caves appear to be populated by monuments, statues, tree, animals and human figures. It takes a long time for these concretions to form but it is difficult to estimate exactly how long as many different factors are involved. A stalactite takes many years and a large column or a rock flow require centuries or even thousands of years. Breaking off a stalactite therefore means damaging beyond repair the patient work of many years. But even just touching the concretion may damage or alter their growth. Therefore while we are happy for visitors to admire the caves, we wouldl ask you to neither damage nor even touch anything in them.

Eccentric and Crystal Formations: a tiny world of enchantment

In the Neptune Caves there are areas where nature seems to have taken great delight in creating concretions of extraordinary and delicate beauty. These eccentric and crystal formations in an enchanting world are an incredible sight. Eccentric formations are those which consist of thin threads of calcite which branch off in all directions, intertwining, curling back on themselves, creating marvellously thin and transparent tangles of rock, made stranger by the play of shadows and artificial light on them. In the small basins of water overflowing with calcium carbonate, calcite crystals slowly form in strange and wonderful shapes, from thin transparent needs to groups of large multifaceted crystals, in shades of color ranging from white through yellow and orange, which reflect the light in dazzling flashes.

By Mauro Mucedda (Sassari Speleological Group)

© 2010 www.portoconte.it