Roquefort-sur-Soulzon, half an hour south of Millau, is the only place where genuine Roquefort cheese is made. Sheep's milk curd is brought from across the surrounding causses and ripened in natural cellars inside the Combalou cliff, where fissures called fleurines drive a steady draft of damp, cool air across the wheels. The penicillium roqueforti mould that gives the cheese its blue veins grows naturally on the limestone.
Three of the producers — Société, Papillon, and Gabriel Coulet — run visitor tours through their caves, with a tasting at the end. Société is the largest and most theatrical; Papillon is the family option with a more personal feel. Tours run roughly hourly in summer and cost a few euros.