Photo: Hot Spring Cave And Basin National Historic Site Banff

A steaming hot spring which is home to the endangered Banff Springs Snail at the Cave and Basin National Historic Site in the town of Banff, Alberta, Canada.

Heated from within the earth's crust, this geothermal hot spring known as the Basin is just one pool found on the slopes of Sulphur Mountain at the Cave and Basin National Historic Site in Banff.

This hot spring is also home to the endangered Banff Springs Snail - a member of the Physidae family. This tiny snail which grows to approximately one centimetre long, survives in water that is low in oxygen but high in hydrogen sulfide, the formula of thermal hot springs. As the snail is very sensitive to disturbance of it's habitat, visitors are asked to refrain from throwing objects into the pool or disturbing the surface.

The hot spring known as the Basin at the Cave and Basin National Historic Site, Sulphur Mountain, Banff, Banff National Park, Alberta, Canada.