Vault of mortarless corbelled stones in a round hut at Espagnac in the Lot département, France. Photo by Dominique Repérant.
<a href="//commons.wikimedia.org/wiki/User:Christian_Lassure" title="User:Christian Lassure">Christian Lassure</a>
CC BY 2.5
<span class="int-own-work" lang="en">Own work</span>