Startled residents of a Russian city inside the Arctic Circle have been posting photos of a local river that has mysteriously turned blood red. Photos published on Russian social media appear to the show the Daldykan River near the city of Norilsk flowing crimson. Russian authorities have yet to establish a reason for the river’s unusual appearance, but local people quickly linked it to a giant metals plant upstream. Russia’s Environment Ministry said it was investigating the plant as the likely cause.

Norilsk is known as one of the most polluted cities on earth, built around factories mostly belonging to the vast metals company Norilsk Nickel. Some Norilsk residents wrote in a local social media group that they believe the river’s biblical shade is linked to runoff from a nearby smelting plant. READ MORE