This is the oldest bookshop in Madrid, according to the Confederación Española de Gremios y Asociaciones de Libreros. Located on the street of the same name, the walls of Calatrava contain an endless source of fascinating anecdotes. It was founded by the protestant cleric Federico Fliedner, and was initially known as Librería Nacional y Extranjera (National and Foreign Library).
Specialized in the protestant religion since its beginnings in 1873, today it offers a wide range of books on all religions. Owing to severe censorship during Franco's time, the bookshop was forced to close between 1936 and 1972. Of interest due to its very specific specialization, the high quality of customer service is also worthy of note.