Potosí became an “Imperial City” following the visit of Francisco de Toledo in 1572.
It and its region prospered enormously following the discovery of the New World’s biggest silver lodes in the Cerro de Potosí south of the city.
The major colonial-era supplier of silver for Spain, Potosí was directly and tangibly associated with the massive import of precious metals to Seville, which precipitated a flood of Spanish currency and resulted in globally significant economic changes in the 16th century.
The whole industrial production chain from the mines to the Royal Mint has been conserved, and the underlying social context is equally well illustrated, with quarters for the Spanish colonists and for the forced labourers separated from each other by an artificial river.
The city and region retain evocative evidence of this activity, which slowed significantly after 1800 but still continues.
This includes mines, notably the Royal mine complex, the biggest and best-conserved of the some 5,000 operations that riddled the high plateau and its valleys, dams that controlled the water that activated the ore-grinding mills, aqueducts, milling centres and kilns.
Other evidence includes the superb monuments of the colonial city, among them 22 parish or monastic churches, the imposing Compañía de Jesús (Society of Jesus) tower and the Cathedral.
Potosí is the one example par excellence of a major silver mine in modern times.
The city and the region conserve spectacular traces of this activity: the industrial infrastructure comprised 22 lagunas or reservoirs, from which a forced flow of water produce the hydraulic power to activate the 140 ingenios or mills to grind silver ore.
The ground ore was then amalgamated with mercury in refractory earthen kilns called huayras or guayras.
It was then molded into bars and stamped with the mark of the Royal Mint.
In 1672, a mint was established to coin silver and water reservoirs were built to fulfill the growing population’s needs. At that time more than eighty-six churches were built and the city’s population increased to nearly 200,000, making it one of the largest and wealthiest cities in the world.
The City of Potosi was inscribed on the World Heritage List in 1987. After 1800, the silver mines were depleted, making tin the main product.
This eventually led to a slow economic decline.
Nevertheless, the mountain continues to be mined for silver to this day.
Due to poor worker conditions (lack of protective equipment from the constant inhalation of dust), the miners still have a short life expectancy with most of them contracting silicosis and dying around 40 years of age.
The city came into existence after the discovery of silver there in 1545 and quickly became famous for its wealth.
Within three decades its population surpassed 150,000, making it the largest city in the New World.
The population declined from a peak of 160,000 about 1650 as silver production waned, and a typhus epidemic in 1719 claimed the lives of some 22,000 residents.
By the early 19th century, Potosí had fewer than 20,000 inhabitants, but the subsequent rise of tin mining again spurred growth.
The site includes the colonial city center and the industrial heritage more close to the mountain, among which are dams, smelters and ore-grinding mills.