Dating from around 4500 BC, Carnac's menhirs remain as mysterious in origin as their English contemporaries at Stonehenge, although religious beliefs and astronomy were doubtless an influence. The 2,395 monuments that make up the three alignements—Kermario, Kerlescan, and Ménec—form the largest megalithic site in the world, and are positioned with astounding astronomical accuracy in semicircles and parallel lines over about a kilometer (half a mile). The site, just north of the town, is fenced off for protection, and you can examine the menhirs up close only from October through March; in summer you must join a €6 guided tour (some are in English). This visitor center explains the menhirs' history and significance, plus it offers an excellent selection of interesting books in all languages, as well as DVDs and regional gifts.
D196, Carnac, 56342, France
/02–97–52–29–81-Maison des Mégalithes