Marin County is the birthplace of the mountain bike, which had its origins in the late 1970s and early 1980s. Steve Potts, who was already building bike frames in Mill Valley in 1980, teamed up with Mark Slate to help meet demand. Charlie Cunningham, in Fairfax, had been building mountain bikes since 1979 with heat-treated aluminum frames which had unique Type II forks, roller-cam brakes, custom-made hubs and other components that were among the first of their kind designed specifically for mountain bikes.