When first observing Canada's Spotted Lake, it can be hard to decide what to make of it. In the winter, it looks like a normal lake, but come summer, the water evaporates, revealing multi-colored spots of various sizes across the lake bed. It looks downright otherworldly...but it's just a rare natural phenomenon. Spotted Lake is a saline endorheic alkali lake-- which means it's got a high pH, it's salty, and it doesn't drain out anywhere-- hence the evaporation each summer. It also contains large amounts of a lot of different minerals, which form deposits when the water dries up, creating the weird spotted effect.
Minerals in the lake include magnesium sulfate (better known as Epsom salts), calcium, sodium sulfates (used to make detergents), silver, titanium and more. The magnesium sulfate is the main cause of the spots' colors as it crystallizes, and varying amounts of water and minerals accounts for the different shades at any given time. The lake is so mineral-rich that during WWI a lot of stuff from the lake was mined and used to make ammunitions for the war effort.
The lake's uses go beyond weapons-- Native Americans knew the lake for its healing powers, and in the late 1970's people were trying to garner interest in building a spa on the lake's shores before the First Nations and the Department of Indian Affairs purchased the land. It's fenced off (walking through it, even when the water is evaporated isn't suggested since it's basically mud, plus it's sacred to the tribes), but there are signs describing the history and healing powers of the lake, they've built a viewing platform and are trying to set up a kiosk/visitor's center as well. In the meantime, you can still get a really good view of the lake, even from the highway, in all its weird, strange glory.
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