The Gavrinis island is famous because of its important passage grave, a megalithic monument from the Neolithic period, belonging to the same broad context as the Breton megaliths of Carnac and Locmariaquer. At the time of its construction, c. 3500 BC, the island was still connected with the mainland. The rich internal decorations make Gavrinis one of the major treasuries of European megalithic art. The tomb is also remarkable for the care taken in its construction and its good preservation.
The stone mound has a diameter of about 50m. The mass of stones forming the cairn is internally structured by a series of walls, subdividing it into separate 'ranks'. It is a characteristic example of Neolithic dry stone architecture. The mound covers a single rectangular (nearly square) slab-built burial chamber, located at the centre of the mound and measuring about 2.5m across. The chamber is built of about 50 carefully placed slabs. The biggest of these is the ceiling slab which weighs nearly 17 tons.
The chamber is reached from outside by a 14m long corridor or passage. Of the 29 orthostat slabs that form the sides of the passage, 23 are decorated with carved symbols and patterns. Some of the symbols appear to represent non-abstract objects, like axes and croziers or staffs. A common horn-like motif may symbolise cattle, a shape conventionally called the shield may be a very stylised human figure. More abstract motifs include zigzag lines, lozenges and snake-like lines.
A replica of part of the Gavrinis passage with its decorated slabs can be visited in the Museum at the megalithic necropolis of Bougon.
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