Objects left for six months to a year under the mineral-rich springs of the petrifying grottoes of Savonnières, France, emerge coated in a perfectly pure white layer of limestone. Bas-relief molds left in the cave for two years at a time (turned once every fortnight) produce fully formed architectural ornaments. The adjacent Museum of Petrifaction collects these beautiful petrified objects–each a marriage of art and nature–for public display and sale.

The grottoes, located just outside the city of Tours, also contain a collection of stalagmites and stalactites, an underground lake, a Gallo-Roman cemetery, and a model of a large and fearsome prehistoric lizard.