The Carnac alignments have been on the French Tentative List (the mandatory first step before inclusion on the World Heritage List) since 1980.
Over the following decade, major excavation and restoration work was undertaken around several monuments, in particular the Er Grah tumulus, the Table des Marchands, the Grand Menhir at Locmariaquer, the Gavrinis cairn at Larmor-Baden, and the Petit Mont cairn at Arzon.
At the same time, the State organised a wide-ranging programme for the conservation and promotion of the Carnac alignments. A scientific committee was established in 1996. That same year, the name of the site on the Tentative List was changed to “Carnac megalithic sites”. At that point, the description of the Property included the three main alignment sites in Carnac, the two Le Ménec enclosures, a gallery grave, a cromlech of isolated menhirs to the north, the large Saint-Michel tumulus (a typical Carnac tumulus), and lastly the Kermario passage grave.
Subsequently, in the face of varied opposition to different development plans for the Carnac alignments, the UNESCO project became less of a priority. The subject came to the fore again in 2005 with the creation of a Public Interest Group for Culture (Groupement d’Intérêt Public à caractère culturel, GIPC): Mémoire de pierres: mégalithes en Morbihan.
All of the GIPC partners (the Département, Region, the municipality of Carnac and the related non-profit associations) entrusted the Bretagne Regional Directorate of Cultural Affairs (Direction régional des affaires culturelles, DRAC) and specifically the Regional Archaeology Department (Service Régional de l’Archéologie, SRA) with the task of defining the principles for a new study zone, covering a territory extending from the Rhuys Peninsula to the Etel Ria.
In 2010, a presentation brochure was published: “World heritage application project, Megalithic heritage of the Gulf of Morbihan: architectural and monumental heritage forming a new cultural landscape.” The renewed UNESCO project is now supported by the local municipalities through their membership of the “Paysages de Mégalithes” association.