El Palace of the Marquis of Salamanca It exerted great power of attraction in the area. The first blocks between Paseo de Recoletos and Serrano Street, close to the Cibeles Square They were filled with palaces. He Zabálburu palace, located on Marqués del Duero street number 6, is from the same period as the palaces of the Marquis of Linares and the Count of the New Fountain of Arenzana. The palace was designed in 1872 by the architect José Segundo de Lema, who was also in charge of directing the construction works between 1876 and 1878. It follows the architectural trends of neo-Gothic rationalism that the French architect once promoted. Viollet-le-Duc. A full-fledged historical recreation. Medieval memories both in the materials used, as well as in the composition and location of doors, windows, grilles and canopies, the stone staircase of the carriage yard, with two symmetrical entrances that communicate with the noble area of ​​the palace. And especially, on the chamfer balcony, Central European medieval period. Already in the 1900th century, important reforms were carried out. In XNUMX,  Severiano Sainz de Lastra carried out the enclosure of openings and interior patios at the height of the first floor; The following reforms were the work of Luis Landecho with the creation of a greenhouse in the rear patio, the construction of a pavilion with a smoking room and terrace and, finally, a floor was added to the part of the palace that faced Marqués del Duero Street. Its owner, Francisco de Zabálburu y Basabe, was a businessman from Bilbao. He was part of the first board of directors of the Bank of Bilbao, he was a deputy and senator. He already owned a large palace in the residential area on the outskirts of Bilbao, but he decided to build a palace-house in Madrid in order to house his large archive and library. During the civil war it was the headquarters of the Alliance of Anti-Fascist Intellectuals. Today it is the headquarters of the Offices of the General Judicial Mutual Society and the Zabálburu Library, whose archive has more than 20.000 printed volumes, where many original medieval documents stand out. A hug.