The Royal Mint is considered one of the oldest and most important examples of industrial heritage. Located on the left bank of the Eresma River, it is one of the few factory buildings from the 16th century that has survived almost intact to this day. It was built by the architect Juan de Herrera for Philip II, who established a mint there that introduced the roller coinage technique in Spain. After its rehabilitation, carried out between 2007 and 2011, the building was turned into a museum that tells the history of currency in the city. The different machines, devices and hydraulic wheels tells about the varied coinage systems that were used in this mint.