Hot Springs National Park ~ http://www.nps.gov/hosp
Congress established Hot Springs Reservation on April 20, 1832 to protect hot springs flowing from the western slope of Hot Springs Mountain. This makes it the oldest area currently in the National Park System--40 years older than Yellowstone National Park. People have used the hot spring water in therapeutic baths for more than two hundred years to treat rheumatism and other ailments. The reservation eventually developed into a well-known resort nicknamed "The American Spa" because it attracted not only the wealthy but also indigent health seekers from around the world. Today the park protects eight historic bathhouses with the former luxurious Fordyce Bathhouse housing the park visitor center. The entire "Bathhouse Row" area is a National Historic Landmark District that contains the grandest collection of bathhouses of its kind in North America. By protecting the 47 hot springs and their watershed, the National Park Service continues to provide visitors with historic leisure activities such as hiking, picnicking, and scenic drives. Hot Springs Reservation became Hot Springs National Park by a Congressional name change on March 4, 1921.
A photo of the visitor center: