Blue cheese is a type of cheese that has a strong, salty flavor and a blue-green mold. One of the most popular types of blue cheese is Stilton, which is a hard, crumbly cheese with a creamy texture and a sharp, tangy flavor. It is made from cow's milk and is usually aged for at least three months. Stilton is named after the village of Stilton in England, where it was first produced in the 18th century.