In 1842 Francisco Lopez dug up wild onions in Placerita Canyon and found a gold nugget in the roots. Almost nothing came of it. Six years later, on January 24, 1848, James W. Marshall spotted flakes in the tailrace of John Sutter’s lumber mill, days before the Treaty of Guadalupe Hidalgo transferred California to the United States. Sutter wanted farmers, not miners, and swore his workers to secrecy. The secret reached San Francisco merchant Samuel Brannan, who bought every shovel, pan, and pickaxe he could find and then walked the streets with a vial of gold shouting the news.

This episode follows the rush from that marketing stunt to its long aftermath. Some 300,000 people set out by way of Cape Horn, the fever-ridden Isthmus of Panama, or the cholera-plagued California Trail. San Francisco grew from about a thousand residents to 25,000, and crews deserted so quickly that an abandoned ghost fleet rotted in the bay. Behind the legend sit vigilante justice, a punishing Foreign Miners Tax, the genocide of Native Californians, rivers choked by hydraulic mining, and the birth of the California dream of sudden fortune.

• Brannan bought pans for roughly 20 cents and resold them at enormous markups, profiting from every miner whether or not that miner found gold.
• Abandoned ships were hauled ashore as warehouses, hotels, taverns, and even a jail, then sunk as landfill. San Francisco’s financial district stands on their remains.
• The Foreign Miners Tax charged noncitizens $20 a month, roughly $770 today, and was enforced mainly against Latino and Chinese miners.
• Hydraulic mining blasted hillsides with water cannons called monitors, raised riverbeds, flooded farm towns downstream, and released thousands of pounds of mercury.
• Of 40,000 people who arrived by sea in 1849, only about 700 were women, so men took on domestic work and danced with each other, marking roles with a handkerchief on the arm.