20-inch mountain bike

The mountain bike is a type of bicycle designed specifically for off-road cycling, including riding on hills, trails, wilderness areas, and gravel or dirt paths. It originated in 1977 on the west coast of the United States in San Francisco. At that time, a group of young people who were passionate about riding beach cruisers came up with the idea while playing on the slopes: "It would be really fun to ride a bike down from the mountains."