Castle of Simancas represents one of Europe's most significant historical institutions, housing the Archivo General de Simancas since 1540. During the 15th century, the House of Enríquez constructed this new fortress atop Moorish foundations, restoring walls and adding a chapel. The Spanish Crown seized it during the Catholic Monarchs' reign and converted it to a royal prison. Philip II's reign initiated a profound transformation as the archive centralized documentation from Spain's far-flung empire. The 16th-century castle, designed by architect Juan de Herrera, earned distinction as the first building constructed exclusively for archive purposes in the Modern Era. It contains an extraordinary collection including documents signed by Columbus, Cervantes, and Philip II, holding UN Memory of the World designation since 2017.
