On the cliff faces one can often see holes, mysterious little windows: these are the "Cluzeaux", cavities cut into the rock to house, shelter or protect the population against invaders and to store foodstuffs. They may be natural caves that were built or fortified in the Middle Ages.

http://roque-st-christophe.com

http://www.la-madeleine-perigord.com

http://jambertie.blog4ever.com/mysterieux-cluzeaux-du-perigord