The Cave and Basin National Historic Site of Canada is located in the town of Banff, Alberta within the Canadian Rocky Mountains, at the site of natural thermal mineral springs around which Canada's first national park, Banff National Park, was established.
Geology and setting :
The Cave and Basin is the lowest component of nine sulphurous hot springs clustered in three groups on the northeast flank of Sulphur Mountain. All are located along the Sulphur Mountain Thrust Fault below Devonian limestones. The water is heated geothermally from an estimated depth of three kilometres. The Cave and Basin is the only underground cavern large enough to comfortably accommodate groups of people.
The built facilities include an artificial tunnel to natural grotto, a replica of the original 1887 bathhouse, the restored 1916 swimming pool and structure, interpretive displays, hiking and snowshoe trails. The 1887 bathhouse, the first structure on the site, proved inadequate by 1902, and a new pool was built in 1904. The stone bathhouse was completed in 1914, designed by architect Walter S. Painter. The pools were closed in 1975, restored in 1985, then closed again in 1992. An interpretive center now uses the structures.
The 1954 caretaker's residence is now used as a tea house. The Banff Upper Hot Springs is a separate facility some 5 km (3 mi) southeast of the Cave and Basin. Many of the early structures were built by detainees held at a World War I internment camp located nearby. The camp held citizens of countries with which Canada was at war at the time, and had a significant Ukrainian contingent.
Almost all of the delicate cave formations had been stripped out of the Cave and Basin immediately following its 'discovery'. According to articles in the Calgary Herald at the time, the construction of the artificial tunnel was contentious even in 1887. In 1924 Western Mosquitofish were introduced into the hot springs in an attempt to control mosquitos. Tropical fish illegally introduced into the lower springs by local aquarium enthusiasts may have contributed to the extinction of the Banff Longnose Dace. Cave and Basin hot springs are also notable as the habitat for the Banff Springs snail, listed as an endangered species in 2000 by the Committee on the Status of Endangered Wildlife in Canada.