The California Gold Rush started in January 1848, when gold was discovered at Sutter's Mill. As news of the discovery spread, some 300,000 people came to California from the rest of the United States and abroad. These early gold-seekers, called "Forty-Niners," traveled to California by sailing ship and in covered wagons across the continent, often facing substantial hardship on the trip. Gold worth billions of today's dollars was recovered, leading to great wealth for some; others, however, returned home with little more than they started with. The effects of the Gold Rush were substantial. San Francisco grew from a tiny hamlet of tents to a boomtown, and roads, churches, schools and other towns were built. A system of laws and a government was created, leading to the admission of California as a state in 1850. New methods of transportation developed as steamships came into regular service and railroads were built. The business of agriculture, California's next major growth field, was started on a wide scale throughout the state. However, the Gold Rush also had negative effects: Native Americans were attacked and pushed off traditional lands, and gold mining caused environmental harm.