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Heritage of Mercury. Almadén and Idrija

Heritage of Mercury. Almadén and Idrija

The property includes the mining sites of Almadén (Spain), where mercury (quicksilver) has been extracted since antiquity, and Idrija (Slovenia), where mercury was first found in AD1490. The Spanish property includes buildings relating to its mining history, including Retamar Castle, religious buildings and traditional dwellings. The site in Idrija notably features mercury stores and infrastructure, as well as miners’ living quarters, and a miners’ theatre. The sites bear testimony to the intercontinental trade in mercury which generated important exchanges between Europe and America over the centuries. Together they represent the two largest mercury mines in the world, operational until recent times.

Patrimoine du mercure. Almadén et Idrija

Le bien inclut les sites miniers d'Almadén (Espagne), où le mercure (vif-argent) a été extrait depuis l'Antiquité, et d’Idrija (Slovénie), où du mercure a été trouvé pour la première fois en 1490 après J.-C. La partie espagnole du bien comprend des bâtiments liés à l'histoire minière du site, notamment le château Retamar, des édifices religieux et des puits traditionnels. Le site d'Idrija présente notamment des entrepôts de mercure et des infrastructures, ainsi que des cités de mineurs et un théâtre des mineurs. Le site témoigne du commerce intercontinental du mercure qui a généré d'importants échanges entre l'Europe et l'Amérique pendant des siècles. Les deux sites sont les deux plus grandes mines de mercure au monde et sont restés en fonctionnement jusqu'à une période récente.

Patrimonio del mercurio (Almadén e Idria)

El sitio comprende las minas de Almadén, en España, donde se ha extraído mercurio (azogue) desde la antigüedad y las de Idria, en Eslovenia, donde se halló mercurio por primera vez en el año 1490. El sitio español incluye varios lugares relacionados con su historia minera, como el castillo de Retamar, edificios religiosos y pozos tradicionales. En Idria hay almacenes e infraestructura relacionada con el mercurio, así como viviendas de mineros y un teatro. Ambos sitios dan testimonio del comercio intercontinental del mercurio, que generó importantes intercambios entre Europa y América durante siglos. Las de Almadén e Idria son las minas de mercurio más grandes del mundo y estuvieron operativas hasta hace pocos años.

source: UNESCO/ERI


source: NFUAJ

Erfgoed van kwik in Almadén en Idrija

Dit erfgoed bestaat uit de Spaanse mijn van Almadén, waar kwik werd gewonnen sinds de oudheid en de Sloveense mijn van Idrija, waar in 1490 na Christus voor het eerst kwik werd gevonden. Het Spaanse gebied heeft bouwwerken die te maken hebben met de mijnbouwgeschiedenis, waaronder het kasteel Retamar, religieuze gebouwen en traditionele woningen. De omgeving in Idrija kent vooral opslagplaatsen voor kwikzilver en de daaraan gerelateerde infrastructuur, maar ook woningen en een theater voor de mijnwerkers. De plekken getuigen van de intercontinentale kwikhandel, die belangrijke uitwisselingen tussen Europa en Amerika genereerde. Samen vertegenwoordigen ze de twee grootste kwikmijnen ter wereld, tot voor kort nog operationeel.

Source: unesco.nl

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Puerta de Carlos IV © Joaquín García Rayo
Outstanding Universal Value

Brief synthesis

Mercury is a relatively rare metal, whose use has long been irreplaceable in a variety of technical, chemical and industrial processes. It has only been produced in substantial quantities and over a long period by a small number of mines worldwide, of which the two largest, until recent times, were at Almadén in Spain and Idrija in Slovenia. These two mining towns, whose origins date from ancient or Medieval times, demonstrate the lengthy period over which a socio-technical system of extraction specific to this metal was in operation, and the process of evolution it underwent. Controlling mercury extraction enabled control of the market, which very quickly became intercontinental in scope because of its decisive role in the extraction of silver from deposits in the New World. A heavy metal, which is liquid at room temperature and has very specific chemical and physical properties, mercury is also a pollutant, which is dangerous for human health. The two sites contain technical remains of large numbers of mine shafts, and their galleries and surface facilities, with artefacts which are specific to the extraction of mercury-bearing ores; they also include significant urban, monumental and infrastructure elements and material and symbolic materials associated with the life styles and social organisation of mercury extraction.

Criterion (ii) : Mercury extraction took place in a very limited number of mines, of which the two largest were Almadén and Idrija. From the Renaissance period in Europe, the activity took on an international dimension. Its worldwide strategic importance increased steadily, particularly because of its role in the working of gold and silver mines in America. The interchanges were at once economic, financial and related to technical expertise.

Criterion (iv) : The mining sites of Almadén and Idrija constitute the most important heritage left behind by the intensive extraction of mercury, particularly in the modern and contemporary periods. This dual testimony is unique, and it illustrates the various industrial, territorial, urban and social elements of a specific sociotechnical system in the mining and metal production industries.


The mining sites of Almadén and Idrija form a coherent whole with complementary components, satisfactorily illustrating all the technical, cultural and social aspects associated with mercury extraction. The elements are present in sufficient number to enable satisfactory interpretation. These are the two most significant sites for this activity to have been preserved, in terms of volumes produced, historical duration, and the completeness of the evidence provided. The integrity of the serial property has been justified.


At both sites, the presence of mining infrastructure elements both underground at on the surface, the presence of technical artefacts linked to mining extraction, its upstream needs (hydraulic energy, wood) and its conversion into “quicksilver” (furnaces), its transport and its storage are authentic. This also applies to the urban and monumental elements, and for the testimony to the miners’ working conditions.

Protection and management requirements

The protection measures for the sites are satisfactory; in both cases they have led to municipal general plans of land use and the control of construction works projects which could affect the sites. These urban and rural planning measures also apply to the buffer zones. At Almadén however, the existence of projects which could have a visual impact on the property and the belated inclusion of the property and its boundaries in the municipal general plan demonstrate the need for closer cooperation between the municipal authorities and the property management entity. For both sites, a satisfactory local management system exists, and the overarching International Committee for the coordination of the serial property has demonstrated that it functions satisfactorily.