Carnac is the greatest concentration of standing stones in the world, and the sheer number is hard to believe until you see it. More than three thousand granite blocks, set in long, straight rows, march across the heathland north of the town, in alignments called Ménec, Kermario and Kerlescan. They were raised by Neolithic people between about 4500 and 3300 BC, long before Stonehenge or the pyramids, and nobody knows exactly why. Theories range from calendars and tombs to ritual processions, and the stones themselves, grey, lichened and leaning, stay silent. The coastal landscape of Morbihan is now recognised on UNESCO's World Heritage list.
Local legend has its own explanation: the saint Cornély, chased by Roman soldiers, turned them to stone to save himself, and the rows are the army still standing in file. The Saint-Michel tumulus, a great mound at the edge of the town, covers a Neolithic burial chamber and has a small chapel on top, with a long view of the bay and the rows of stones. The country around is a low, windswept plateau of gorse, heather and pines, with the Atlantic only a few kilometres away, and the light is often soft and silvery.
Riding here is easy and pleasant. The roads across the plateau are mostly flat and straight, with gentle bends through villages of low granite houses, and the coast roads run beside beaches and oyster beds. Sea wind can be strong and cold, even in summer, and weather arrives quickly off the Atlantic, so pack a waterproof layer. Plouharnel, Carnac and Auray are all within easy reach, and Auray, a town of twelve thousand people with a pretty old harbour at Saint-Goustan, is the best place for fuel and a longer lunch, though Carnac has stations and bakeries as well.
Try to walk in the stones early, before the coaches arrive. The alignments are best seen in the low, golden light of morning or evening, and in the busy season, access to some stretches is limited to protect the ground, with fenced areas and viewing paths. Buy salted-butter caramels in town as a souvenir, and watch the tide go out across the bay.