Leadville, Colorado

Leadville began with a disappointment. Prospectors chasing the Colorado Gold Rush worked California Gulch beginning around 1860, but the placer gold played out fast, choked by a heavy sand nobody could sell. That sand turned out to be cerussite — lead carbonate rich in silver — and its recognition around 1874 set off one of the richest silver rushes in the world. In 1877 mine owner Horace Tabor and smelter man August Meyer helped establish the town, and within a few years tens of thousands of people had poured into the Upper Arkansas Valley. Silver here launched some of the most famous fortunes in American history: Horace Tabor rose from a general store to become a U.S. senator, Meyer Guggenheim got his start in Leadville mining and smelting, and Margaret Tobin — later Molly Brown of Titanic fame — married J.J. Brown here in 1886, the couple's fortune arriving with a Leadville-area gold strike.

The boom didn't last unbroken. In 1893 the federal repeal of the Sherman Silver Purchase Act collapsed silver prices and gutted Leadville's economy — Horace Tabor himself lost his fortune. But the mountains around Cloud City held more than silver. Miners pivoted to gold, lead, zinc, and copper, and in the 20th century the story moved uphill to Fremont Pass, where the Climax mine became one of the world's largest producers of molybdenum — a metal that hardens steel. Climax grew its own company town on the pass, which was moved down to Leadville in the early 1960s to clear ground for more mining. After long dormancy, Climax resumed molybdenum production in 2012, and mining, in some form, has never fully left.