We've already visited cave-dwelling off grid farmers in Utah, but living underground is nowhere near as rare as you might think. In fact, in parts of France cave dwellings have been used as a low cost means to create durable, cool structures for homes, farms (for raising silkworms and mushrooms) and even discos and hotels. Here we are taken on a visit to Henri Grevellec's home in an old disused quarry.
From an old garage turned stunning tiny house to a Spanish ghost town that was transformed into a self-sufficient ecovillage, Fair Companies have already brought us many fine examples of sustainable, resourceful architecture over in Europe. (Their US offerings are also worth a view—most notably this beautiful home built from salvaged car parts.) But it's this kind of exploration of traditional building systems that is perhaps the most enlightening.