Timpanogos Cave National Monument in American Fork Canyon preserves a three-cave system—Hansen, Middle, and Timpanogos caves—and the Timpanogos Cave Historic District. Discovered in stages from 1887 through 1921, the caves were later linked by Works Progress Administration tunnels in the 1930s, creating the route used for guided tours. Established in 1922 and managed by the National Park Service since 1933, the site is known for colorful speleothems, especially twisting helictites, as well as formations such as flowstone, drapery, stalactites, and stalagmites. Its history has centered on protecting fragile caves from damage while allowing limited public access in a geologically distinctive setting.