A chance discovery on January 24, 1848, profoundly shaped the destiny of Californiaand the world. On this day, in a river valley that quickly became ... Show synopsis A chance discovery on January 24, 1848, profoundly shaped the destiny of Californiaand the world. On this day, in a river valley that quickly became the town of Coloma, James W. Marshall found gold in the tailrace of a sawmill he was building for John Sutter. The discovery precipitated the largest gold rush in history, bringing an estimated 300,000 fortune-seekers from all over the world in just a few years. By 1849, Coloma mushroomed into a town of 10,000 people, most of them transient miners. Soon, the town became more permanent, with grand hotels, fine homes, and stout brick buildings. In 1857, with the moving of the county seat to Placerville, Coloma entered a period of relative slumber. By the 1870s, however, Robert Chalmers presided over the largest winery outside of the Napa Valley. Orchards and ranches proliferated. The discovery site later became a state park. By the 1970s, tourism brought in even more wealth with the advent of the white-water rafting and kayaking industry.