At the end of Cave Avenue, Cave and Basin National Historic Site (403/762-1566, summer daily 9 a.m.–6 p.m., the rest of the year Mon.–Fri. 11 a.m.–4 p.m., Sat.–Sun. 9:30 a.m.–5 p.m.; adult $4, senior $3.50, child $2.50) is the birthplace of Banff National Park and of the Canadian National Parks system.

After its discovery in 1883—lounging in the hot water was considered a real luxury in the Wild West—bathhouses were installed, and bathers paid $0.10 for a swim. The pools were eventually lined with concrete, and additions were built onto the original structures.

Ironically, the soothing minerals in the water that had attracted millions of people to bathe here eventually caused the pools’ demise. The minerals, combined with chlorine, produced sediments that ate away at the concrete structure until the pools were deemed unsafe in 1993.

Although the pools are now closed for swimming, a narrow tunnel winds into the dimly lit cave, and short trails lead from the center to the cave entrance and through a unique environment created by the hot water from the springs.