One of the largest libraries in the world and the main national archive for Spanish literature, housed in a massive neoclassical building on the Paseo de Recoletos dating from 1896. The library itself is not open for general browsing without an accreditation card, but the Museo del Libro on the ground floor is free and open to the public, displaying rare manuscripts, maps, and printed books from the collection.
The building's reading rooms are occasionally opened for special visits; the permanent exhibition covers the history of writing and book production in Spain from the medieval period onward. The attached Museo Arqueológico Nacional at the same address has a separate entrance and charges admission. Metro Colón.