In the Saumur region of France there are over a thousand miles of underground tunnels and thousands of caves, known as “troglodytes”, homes, hotels, restaurants, museums, wineries, farms (silkworms, mushrooms, snails) and even a disco and a zoo (for nocturnal animals like bats).

What makes this land so perfect for underground dwellings is its very malleable rock. 100 million years ago, this part of France was covered by sea. When the water receded, it left a layer of tufa, or tuffeau, a type of limestone that turned out to be ideal for building castles, churches and homes in the surrounding area during the Middle Ages.

All of this quarrying created lots of tunnels and caves that turned out to be ideal homes, especially for quarrymen. Up until the early 20th century, troglodyte living was still common in the area. Even entire villages, like that of Louresse-Rochemenier, were housed underground.

In 2000, when Henri Grevellec retired from teaching, he bought an old quarry and moved into one of the old caves. On his property in Grezille, France, there are 6 caves that had once housed quarry workers centuries ago.

The site was abandoned when Grevellec purchased it, but he cleared away the growth and renovated the caves himself. He put in a modern kitchen and bathroom and in his bedroom (at the far back of the cave) he added a skylight to improve air circulation and add a bit of light.

Of the 6 original caves, one became a guest room (which he connected by tunnel to his main home), another is now his workshop (for his stone-working tools), another he left as it once had been (complete with wood-burning oven) and he uses part of one as a wine cellar.

Grevellec says the temperature in his cave home is naturally temperate. He doesn’t need air conditioning and leads much less heat than a normal home because the earth walls act to naturally regulate the indoor temperature (see more on earth sheltering for details on earth walls as thermal mass).

In this video, Grevellec shows us his cave home, the fossils he has discovered on his property, his stone-working tools and he talks about his love of the rock.

* Music credit: “Ranz des Vaches” by Kevin MacLeod, “The Forest and the Trees” by Kevin MacLeod, “Divertissement” by Kevin MacLeod (http://incompetech.com)