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Almadén on the Mercury Route of the Intercontinental Camino Real

Property names are listed in the language in which they have been submitted by the State Party.

Spain (Europe and North America)

Date of Submission: 27/04/2007
Criteria: (ii)(iv)(v)
Category: Cultural
Submission prepared by:
Ministry of Culture
State, Province or Region:
Castilla la Mancha
Ref.: 5137


The significance of the role played by Almadén on the Intercontinental Mercury Route, on which its outstanding universal value is based, was considered in defining the specific type of site proposed for the World Heritage List. For this reason the proposed site must be analysed as a fundamental component of a cultural itinerary.

The Camino Real (royal road) embraces the entire geographical network which united three continents during all of the Middle Ages. Europe, America and part of southeast Asia were very closely linked, comprising a structure which linked ports and cities, towns and travel hubs for the purpose of guaranteeing the stability of the economic model based on trade monopoly and other cultural values of a more spiritual vein under the Spanish Monarchy.

The same route regulating the flow of commodities and products also sparked human, cultural and religious exchanges giving rise to the concept of the "New World". Its true geographical dimension is expressed in terms of the radius of its scope affecting three continents, several archipelagos, two oceans, seas, rivers, lakes, historic roads and paths with their respective sections and scales.

Historically speaking, the Mercury Route included the extraction sites and destination points of that material and the roads and procedures established for its sea-land transport, as well as the methods discovered and employed for the optimisation of its use in the amalgamation of precious metals in America, the resulting distribution routes and its impact on the world economy at the time, together with other social and cultural implications.

The area surrounding the Almadén mines encompasses different types and scales of elements including geological, geographical and geo-morphological aspects, landscape, roads, mines, other engineering works and the historic city-centre of Almadén.

The Almadén mines are comprised of a system of galleries and shafts from different periods ranging from the Middle Ages to the present day where one can observe the stratification of these past undertakings.. There is also a mineralogy and metallurgy area, administrative buildings and warehouses with constructions and installations from different historic periods.

Almadén is surrounded by rough land featuring dumpsites on one side and the oldest part of the town on the other whose subordination to the mine is plain to see.

The area proposed for inscription is inclusive of the following sites:

  1. The Almadén mine with all the corresponding elements, i.e. galleries, shafts, a mineralogy-metallurgy area, workshops, dumpsites and administrative and social buildings. This area also includes the Bustamante furnaces (1646), the Buitrones enclosure (17th century), the door of Charles IV (1795), as well as other highly valued elements.
  2. Identifiable stretches of the road to Seville, city from which the mined mineral was shipped to America.
  3. The historic city-centre of Almadén, from the mine to the Plaza de la Constitución. The town itself is home to several important monuments, for instance the remains of Retamar Castle (14th century), the House of the Inquisition or Fúcares (15th century) and the Mining Academy (1785), as well as domestic buildings of historical and typological value.
  4. The remains of the Real Cárcel de Forzados (forced labour prison dating to 1754).
  5. The San Rafael Royal Mining Hospital (1776) and its immediate surroundings.
  6. A hexagonal bull ring (1757) and its immediate surroundings.
  7. The landscape immediately surrounding the mine.
  8. The San Carlos winch at the La Concepción mine (17th century) in Almadenejos and its immediate surroundings.

Almadén is considered the world's largest mercury deposit and has produced approximately a third of the mercury consumed by man down through the ages. Approximately 7.5 million containers each holding 34.5 Kg. of metal have been extracted from the mine, and hence its uniqueness as natural and cultural heritage.

Cinnabar (mercuric sulfide) from Almadén was mined by the Romans in the form of vermillion for cosmetic use while the mercury content (hydragirium) had no known applications. References to cinnabar from Almadén appear in texts written by Theophrastus, Plinius the Elder and Vitruvius. Following the incorporation of Hispania into the Roman Empire, the Almadén mine became the main source of vermillion, eclipsing other less abundant sources.

As concerns mining which was of great economic importance, the intercontinental Camino Real focused on the mercury trade needed to amalgamate precious metals mined in America using the method developed by the native of Seville, Bartolomé de Medina, in New Spain in 1554. This procedure was especially important in the many Mexican silver mines where there was a lack of firewood to extract the silver by roasting and the ore was poor. During this period, Almadén enjoyed extraordinary splendour and mining was rationalised and developed.

Owing to strong demand for this liquid metal, mercury deposits were found in Huancavelica, Peru in 1563 which especially met domestic demand and supplied New Spain with mercury only when Almadén was unable to keep up with demand, the same being true of the distant Idria deposit during the Habsburg period. Aludel ovens were developed in Huancavelica for mercury distillation. This technology was subsequently introduced to Almadén where they were called Bustamante furnaces.

The main transport route used for Almadén-mined mercury shipments was through Sanlúcar de Barrameda or Seville to the port of Veracruz. In the year 1559 the modest amount of 264 quintals was delivered to this American port but just ten short years later, in 1570, the amount had risen to 1743 quintals and from the year 1614 to 1630, that amount rose at an annual rate of 4000 quintals.

Development in Almadén during the 18th century was more than just technological. A hexagonal bull ring complete with living quarters (the second in Spain) was built to finance the first hospital for miners suffering from "mercury sickness". The world's fourth mining school was also built in line with German technology as was the prison known as the Cárcel de Forzados, where prisoners were forced to work in the mines. The fact that in the year 1800 New Spain exported 60% of the world's silver is evidence of the dependence on Almadén's mercury.

The Almadén mine site is characterised by a landscape formed by the typical dumpsites.

The morphology of the town of Almadén reflects the latter's historical evolution always linked to the mine. The oldest part of the town in the vicinity of Retamar Castle is comprised of narrow winding streets typical of a Moorish settlement on an elevated outcrop. The town expanded in the direction of the Cerco de Buitrones and the San Teodoro mine shaft which already in the 18th century had begun to spread, but always maintaining the mine at the centre of all expansion.

The landscape of the Almadén district is characterised by a very clear contrast between rough land and rock formations and much more gentle relief with Mediterranean forest distributed according to the millenary and characteristically Iberian tradition of pasture land.

Justification for Outstanding Universal Value

Satements of authenticity and/or integrity

The Almadén mine is characterised by a stratification which commenced with Roman artefacts in the road to Seville and include the different historical periods during which technological and architectural stylistic changes took place. In the case of the galleries, their history can be read by undertaking a vertical analysis. The mine shafts have maintained the different strata, some of which can be seen readily by the naked eye. Elements added for reason of safety or teaching purposes clearly correspond to the present.

Integrity is generally outstanding except in the case of the Retamar Castle and the Forced Labour Prison. Even in these cases, however, what has been conserved allows one to gain insight into the site's history.

We should highlight the landscape conservation work undertaken to maintain the contours of the dumpsites.

In the town of  Almadén, the current morphology clearly illustrates the stratification of the urban layout from the earliest streets in the vicinity of the Retamar Castle to the new developments built in the 1960's. The historic city-centre has maintained the integrity of this layout and the exceptional homogeneity of its morphology. Very little has been changed.

Comparison with other similar properties

The Intercontinental Camino Real can be compared with other cultural itineraries but is differentiated in terms of its complex and wide-ranging historical functionality and geographical extension and for comprising the fundamental support system for relations between Europe and a significant portion of America. The Intercontinental Camino Real had an enormous socio-economic impact and sparked the development of cultural models on both shores of the Atlantic.

The Almadén mercury mines are on a par with other sites on the World Heritage List, the main differences being their historic functionality and their significance as part of the cultural itinerary for which they were the driving economic force. Also for their economic importance down through the history of humanity as the number-one producer of mercury in the history of the world. Almadén mercury production down through the ages was two and a half times greater than that of the world's second most productive mine (Idria in Slovenia) and nearly four times greater than the third most productive (Monte Amiata in Italy).

Almadén is characterised by its particularly high level of integrity and authenticity both in terms of the mine as well as the historic city-centre and the surrounding landscape.