Founded under Charles III in 1785, these are housed today in the old 16C Exchange building built by Juan de Herrera, the architect of the Escorial. Inside, this sober Renaissance, building is a superb marble 18C staircase. On the upper floor, large rooms with superb vaulted ceilings contain countless documents relating to the discovery and the colonisation of America. There you will find the signatures of Christopher Columbus, of Magellan, of Cortès, etc.