The alignments and tombs around Carnac were created during the Neolithic transformation of Brittany, when farming communities established permanent territories along the Morbihan coast. Recent dating places much activity between about 4800 and 3500 BCE, though construction and reuse extended across generations. Communities raised thousands of granite standing stones in long rows at Ménec, Kermario, Kerlescan, and neighboring sites. They also built passage graves and great mounds such as Saint-Michel. These works required coordinated labor to select, move, shape, and erect stones whose meanings were embedded in ceremony, ancestry, and control of the landscape.

The monuments were not a single project or a simple stone army. Alignments changed direction, incorporated local topography, and related to enclosures, tombs, and routes. Some stones were reused fragments of earlier monuments, showing that builders deliberately reworked places already considered ancient. Grave goods, polished axes, pottery, and organic remains connect the megaliths to wide exchange networks along the Atlantic façade. The immense scale of Carnac made the region one of Europe's densest concentrations of Neolithic monuments and suggests communities capable of sustaining shared ritual projects without cities or centralized states.

Later peoples repeatedly reinterpreted the stones. Bronze and Iron Age communities buried their dead and worked within the inherited landscape. Roman occupation introduced roads and settlements, while Christianity generated legends intended to explain or domesticate the pagan-looking monuments. One famous story held that Saint Cornély turned a pursuing army into stone. Chapels, crosses, field boundaries, and farms became interwoven with the alignments. Some stones were broken for building material, removed to clear fields, or incorporated into walls.

Antiquarian investigation intensified in the eighteenth and nineteenth centuries. Scholars debated whether the stones were Celtic temples, battle memorials, astronomical devices, or burial monuments. Prosper Mérimée and other preservation advocates drew state attention to the damage caused by quarrying and agriculture. France began acquiring and protecting parcels in the nineteenth century. Excavators including James Miln and Zacharie Le Rouzic documented monuments, restored fallen stones, and created collections, although early interventions sometimes rearranged evidence according to contemporary assumptions.

Twentieth-century archaeology replaced many speculative explanations with stratigraphic excavation, regional survey, and scientific dating. Fencing and controlled access were introduced to address erosion caused by heavy visitation. New remote sensing and preventive archaeology continue to reveal buried features, demonstrating that the visible rows are only part of a much larger ceremonial landscape. Conservation must balance research, farming, tourism, vegetation, and the wishes of surrounding communities.

In 2025 UNESCO inscribed the Megaliths of Carnac and the shores of Morbihan as a World Heritage property, recognizing a broad network rather than only the best-known alignments. Carnac's history is therefore one of repeated acts of meaning-making: Neolithic construction, later burial and settlement, Christian legend, destruction and reuse, antiquarian restoration, and modern scientific protection. The stones endure not as an unsolved riddle detached from people, but as evidence of communities continually reshaping their relationship with an ancestral landscape. Because documentation standards changed over time, some restored stones and excavated areas also preserve the history of archaeology itself. Current management treats old photographs, plans, ownership records, and earlier interventions as evidence, helping researchers distinguish Neolithic construction from the alterations made by farmers, antiquarians, restorers, roads, and visitors.