Roquefort is France's great sheep's-milk blue cheese, a moist, crumbly white paste shot through with blue-green veins of Penicillium roqueforti. Aged in the natural limestone caves of Combalou above the village of Roquefort-sur-Soulzon, it is sharp, salty and tangy, with a buttery richness and a piercing peppery-mineral bite — long called the king of cheeses and the cheese of kings.