— les troglodytes — is in the region of Saumur. The mines are a perfect environment for wine cellars. Many of the larger caves have become champignonnieres — i.e., are used for growing a commercial variety of mushroom, which is transported daily to the markets of Paris. Architecture Numerous buildings in the Loire Valley, from the most modest to the most grandiose, were built from blocks of tuffeau stone, including the Château de Beaulieu near Saumur, the Château d'Ussé and the Château de la Motte d'Usseau, and many worker's cottages at Longères. See also List of types of limestone Building stone Limestone Geography of France Underground mines in France