In Antarctica’s McMurdo Dry Valley there is a “the waterfall is bright red, like blood running from a cut in the glacier” according to Smithsonian Magazine as reported on the Australian science website, ScienceAlert.
Here is the explanation behind this wonder from Smithsonian Magazine: Millions of years ago, a salt lake formed when sea levels rose and flooded the region. Ice then settled on the salt lake and formed glaciers which caused the lake to be separated from the rest of Antarctica and kept it underground. The lake became even saltier than it already was over time which made it impossible to freeze. On top of that, the water hasn’t been exposed to sunlight, has no oxygen supply and is rich in iron. When the water from the lake gets through the glacier and comes into contact with air, this iron-rich water rusts and gives it its bright red appearance as it falls.
Now you know!