Located between the island of Gavrinis and Penbert Point, Arzon, the islet of Er Lannic has the distinction of being home to two semi-circular megalithic enclosures. These edifices are excellent evidence of rising sea levels since the Neolithic, since they are no longer visible at all times: while half of one can still be seen at high tide, the other half appears only at low tide; the other is now always under water. They lie along a direct line of sight with the Gavrinis tumulus; their central position in the present-day Gulf suggests that they are also linked with the sites in the surrounding present-day municipalities of Locmariaquer, Arzon, Sarzeau, and Île-aux-Moines.
These monuments are of generous proportions: the submerged southern enclosure is 61 metres in diameter; the northern enclosure measures around 66 metres. The two enclosures comprise around 114 standing stones; these were undoubtedly inserted into a retaining embankment made of stones and earth.
The enclosures are listed historic monuments, excavated and restored in the early twentieth century by Zacharie le Rouzic, one of the greatest archaeologists of that time. The site has yielded a large number of ceramics, especially of a particular kind: pedestalled cups, a few examples of which are on display in a showcase at the Carnac Prehistory Museum.
The islet is not accessible today as it is a bird reserve, but the enclosures can be seen by boat and from many points around the Gulf of Morbihan.
©A.Lamoureux-GolfeduMorbihanVannesTourisme
©FanchGalivel/PaysagesdeMégalithes