Hot Springs National Park is the only national park that protects a unique combination of lithology, geologic structure and water sources that produce the only non-volcanic geothermal springs of such a high quality (e.g., temperature, taste, color, and odor) in the United States. This national park, first designated as a reservation by Congress in 1832, is the only unit of the National Park Service mandated to give away its primary natural resource, the geothermal water, to the general public in both an unending and unaltered state. Bathhouse Row within the park contains the largest collection of early 20th century bathhouses in the country.