The Carnac stones are the largest concentration of prehistoric megaliths in the world: more than three thousand standing stones arranged in long parallel rows across about four kilometres of heath. The three main alignments — Le Menec, Kermario and Kerlescan — each contain a thousand or more stones arranged in eleven or thirteen rows, with the largest stones at the western (sunset) end.
Access is regulated. From October to March you can walk freely among the stones; from April to September the alignments themselves are fenced and you visit on a guided tour booked in advance from the visitor centre. The free roadside view from the D196 still gives a good sense of the scale.
A short distance away in Carnac village, the Musée de Préhistoire holds one of the best Neolithic collections in Europe — much of the material excavated from the alignments and the surrounding tombs.