Castle of Simancas

Simancas, Spain, Spain

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Castle of Simancas stands as a 15th-century fortified complex in the central Spanish town of Simancas, Valladolid province, originally built by the Enríquez family, Admirals of Castile, atop an earlier Moorish fortress between 1467 and 1480.

Seized by the Catholic Monarchs, it served as a high-security royal prison before Philip II transformed it in 1540 into the world's first purpose-built state archive, the Archivo General de Simancas, housing over 35 million documents in fireproofed facilities.

Featuring robust walls, battlements, a deep moat, bridges, and later Herrerian-style additions like a grand patio and chapel, it blends defensive might with administrative elegance, now open for public visits amid its historic town center.