A gold rush is a period when large numbers of people hurry to a place where gold has been discovered, hoping to get rich quickly. The most famous American gold rush started in 1848 when someone found gold in California. News spread, and by 1849, about 300,000 people had rushed to California from all over the world, which is why they were called the “forty-niners.”

During a gold rush, whole towns spring up almost overnight near mining areas. People leave their jobs, families, and comfortable lives behind, traveling thousands of miles on the slim chance they might strike it rich. Most gold rushers never find much gold at all. The real fortunes often go to clever businesspeople who sell supplies, food, and equipment to the miners. During the California Gold Rush, a man named Levi Strauss became wealthy by selling sturdy work pants, which we now call jeans, to miners, not by mining gold himself.

Besides California, major gold rushes happened in Alaska, Australia, and South Africa. These rushes transformed entire regions almost instantly, building cities, creating chaos, and changing the course of history.

Today, people use gold rush to describe any situation where everyone rushes toward the same opportunity, like when a new technology creates a “tech gold rush” with entrepreneurs competing to build the next big thing.