The California Gold Rush begins on January 24, 1848, when gold is discovered by James Marshall at Sutter's Mill in Coloma, California.

News of the discovery soon spreads, resulting in some 300,000 men, women, and children coming to California from the rest of the United States and abroad.

These early gold-seekers, called "forty-niners," travel to California by sailing ship and in covered wagons across the continent, often facing substantial hardships on the trip.

While most of the newly arrived are Americans, the Gold Rush attracts tens of thousands from Latin America, Europe, Australia and Asia.

At first, the prospectors retrieve the gold from streams and riverbeds using simple techniques, such as panning, and later develop more sophisticated methods of gold recovery that will be adopted around the world.

Gold, worth billions of today's dollars, is recovered, which leads to great wealth for a few; many, however, return home with little more than they had started with.The effects of the Gold Rush are substantial.

San Francisco grows from a tiny hamlet of tents to a boomtown, and roads, churches, schools and other towns are built.

A system of laws and a government are created, leading to the admission of California as a state in 1850.

A unique social structure evolves.

New methods of transportation develop as steamships come into regular service and railroads are built.

Agriculture, California's first big attraction, develops on a wide scale throughout the state as gold mines produce less.

However, the Gold Rush also has negative effects: Native Americans are attacked and pushed off traditional lands, race and ethnic tensions form, and gold mining causes environmental harm.