In 1549, a miner named Collin Schwartz uncovered the Saint-Jean vein, a vast silver deposit extending in the subsoil of the Val d'Argent, in Alsace. The discovery triggered an unprecedented mining booming in the region. Some 3,000 men and women came to settle in the valley to earn their living in the mines. The via ferrata, created in the Tellure mining park in 2009, allows exploring the galleries they dug little by little during the Middle Ages and the Renaissance. Veins of silver, copper, and white quartz still emerge from parts of the gneiss walls.