The Boise Natatorium, also known as the “Nat” was first constructed under the direction of John C. Paulsen in May of 1892. Located on Warm Springs Avenue, the Nat utilized a hot water source on the far side of Table Rock. Boise Artesian Hot & Cold Water Company, which was founded by C.W. Moore after he moved to Warm Springs Avenue in 1891, designated Paulsen to design a hot water bathing resort after the discovery of a great water source near the Old Penitentiary (Kelly Hot Springs). Despite the economic downturn of 1893, the Natatorium, a Union Pacific passenger station, and a department store helped solidify Boise’s downtown area during a time of recession. Soon after its construction, other houses were built on Warm Springs, which used the same geothermal source of hot water. Many of these houses still remain and use geothermal energy to heat their house. Both Moore and Paulsen had an extensive impact on the development of the city of Boise.
The original Nat included a 125-foot long pool, a dining room, clubrooms, a saloon, gymnasium, dance floors, card rooms, tearooms, and baths. Huge wooden truss arches, which were 80 feet in diameter, enclosed the whole interior. A mezzanine also ran around the entire pool. Additionally, there was an artificial waterfall created to go over a 40-foot lava rock diving platform at one end. Patrons could plunge in the soothing 98-degree water from a two-story copper slide that was located inside. The Nat was constructed for $87,000, which in today’s economy would have been over $2,100,000.
The Nat became such a popular attraction in Boise, that in 1901, Idaho’s first Inaugural Governor’s Ball for Frank W. Hunt took place on top of the pool. A large cover was placed over the pool to serve as a dance floor for all the guests. The ball featured incandescent lighting and hanging ferns all along the inside. Part of the old Nat’s success lies in the fact that there was streetcar system running right next to the building. Residents were skeptical about the reliability of geothermal heating before Moore built his house. His house showed that this new system of heating could work, so other affluent Boiseans started to settle on the avenue. Noticing this, the Boise Rapid Transit Company built a trolley line right through the area. People could ride the cars to Warm Springs for a nickel. In addition, the famous White City Amusement Park, named after the “white city” that was built during the World’s Columbian Exhibition, was located next to the pool. The park was built in 1907, and offered attractions such as dance pavilions, boating docks, penny arcades, and a roller rink. Just as Clarence Darrow called Boise the “Athens of the Sage-Brush”, Hiram T. French named the Natatorium “The Taj Mahal of the West”.
The architecture of the old Nat resembles a Moorish revival, which stood out from the popular Queen Anne “gingerbread” style of the time. Two, six-story towers protruded on each side of the entrance, which gave the Nat almost a turreted feeling. The keyhole arches, also known as horseshoe arches, set the Nat apart from almost every single other building in Boise at the time. It managed to be an exotic attraction because of the Moorish style, but not look imitative of any real Eastern building. Moorish revival, which was a Romanticist fascination with all things oriental, reached it height during the mid 19th century. Because the Nat was built after this period, it seemed to try to “look back” to earlier times and places. This all-wooden building stood out as a grand statement to the rest of the country.
Unfortunately, steam from the hot water caused the wooden beams to eventually rot. During a windstorm in 1934, swimmers were told to move over to the shallow end due to safety reasons. Boise native and Natatorium enthusiast, Clarence Moser described the scene: “There was a big storm outside. We got down to the shallow end and we hadn’t been down there five minutes ‘til one of those big beams fell down in the pool. And lucky it never hit a person. Everybody come out of there, they condemned it then.” Soon after, the city of Boise decided to purchase the swimming pool and reopen facility. After it was demolished, the geothermal water supply to the Nat was cut off. Because the destruction of the Nat occurred during the Great Depression, plans were never created to restore the building to its former glory. Both the removal of the original Natatorium and the eventual replacement of trolley cars with busses signified the end of an era in Boise.
The Natatorium pool still remains in its original location next to Adam’s elementary. Boise residences can recall their experiences, as far back into the 50’s and 60’s, of trying to escape the summer heat by swimming in the open pool. The architecture of the new building resembles a Greek revival layout with its Doric pillars and semi-circle arches. These embellishments ordain the building on all four sides. Additionally, a pointed pediment sits on the roofline above the entrance to the pool. The structure as a whole is very simplistic and lackluster when compared to the original building. It contains a large waterslide known as the Hydrotube, along with a large in-ground pool that has a maximum depth of 12 feet. The city is currently trying to reconnect the Nat to the geothermal water line that it once was a part of. Located near the Greenbelt, the current Natatorium still stands as a landmark in Boise and will remain as a historical attraction for years to come.