Alcazaba of Mérida

Mérida, Spain, Spain

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The Alcazaba of Mérida, in Mérida, Extremadura, Spain, stands as the Iberian Peninsula's oldest Muslim fortress, constructed in 835 by Emir Abd ar-Rahman II of Córdoba to control the rebellious city.

Built near the Roman bridge over the Guadiana River using repurposed Roman and Visigothic granite materials, it features a square enclosure with 130-meter sides, 10-meter-high walls averaging 2.7 meters thick, and 25 quadrangular towers acting as counterforts, surrounded by a moat except along the river.

Designed by architect Abd Allah with Byzantine influences, it functioned as an administrative hub, governor's residence, and military stronghold with later additions like albarrana towers by the Order of Santiago after the 13th-century Christian reconquest.