Almadén, Spain, is a town and municipality in the province of Ciudad Real, within the autonomous community of Castile-La Mancha. The town is located at 4° 49' W and 38° 46' N and is 589 meters above sea level. Almadén is approximately 300 km south of Madrid in the Sierra Morena. The name Almadén is from the Arabic word المعدن al-maʻdin, meaning 'the mine'.Originally a Roman (then Moorish) settlement, the town was captured in 1151 by Alfonso VII and given to the Knights of the Order of Calatrava.The mercury deposits of Almadén account for the largest quantity of liquid mercury metal produced in the world. Approximately 250,000 metric tons of mercury have been produced there in the past 2,000 years.