The silver mine of Saint-Jean Engelsbourg was exploited from 1549 to 1907. Its galleries form a vast underground network under Tellure Park. The mine's development took place between the 15th and 16th centuries, accelerated by the massive arrival of miners from Saxony and Bohemia. The Thirty Years' War and geological hazards hampered exploitation until the end of the 18th century. The last cobalt mine of the site officially closed in 1976. In 2009 a via ferrata was set up in Tellure Park that allows exploring the galleries as close as possible to the former ore veins.