The Canadian National Park system was effectively born at these hot springs, discovered accidentally by three Canadian Pacific Railway employees on their day off in 1883 (though known to Aboriginals for 10,000 years). The springs quickly became a bun fight for private businesses offering facilities for bathers to enjoy the then-trendy thermal treatments.To avert an environmental catastrophe, the government stepped in, declaring Banff Canada's first national park in order to preserve the springs.
There's no longer swimming here, but the site reopened as an impressive museum in May 2013 after a two-year restoration. The original cave and the old outdoor springs and bathhouse (closed in 1971) can be viewed, alongside a lovingly curated cinematic exhibition of Parks Canada's cache of 44 national parks.
Leading out from the complex are two walking trails: an interpretive walk along boardwalks to the cave vent; and the 2.3km Marsh Loop Trail across the park's only natural river marsh.