La Pierre Folle is a dolmen. What's that? A dolmen is a stone structure dating from the megalithic era — five to six thousand years ago. There are many hundreds of dolmens in France.
The one called Le Dolmen de la Pierre Folle ("the crazy rock") is located not very far east of the town of Valençay, with its famous château, and just outside the village of Bagneux near the border between the Indre and the Cher départements. That puts it about 40 km or 25 miles east of Saint-Aignan.
The table stone at La Pierre Folle is nearly five meters (15 ft.) long and three meters (10 ft.) wide. It sits on top of seven upright stones. Nobody really knows who built it, or why. It's often assumed that dolmens were grave sites — prehistoric tombs.
A man named Ludovic Martinet did archeological work at La Pierre Folle in 1875. On the site, he found several fragments of pottery but no human bones at all. What he found mostly was fragments of flintstone that had to have been transported to the site from elsewhere, because the only local stone is sandstone.
To find the Pierre Folle dolman you drive for a mile or two through the woods...
...until you see this sign on the side of the road.
La Pierre Folle is not really easy to find. There are several other prehistoric stones in the area — menhirs — according to what I've read. They are even more difficult to locate and I didn't find them when I drove over to the area with CHM a few weeks ago.