In this photo—which is not black and white—a worker stands in a sylvinite mine tunnel 437 yards (400 meters) underground.
The words “Russian salt mine” don’t usually make you think of stunning images. Unless, of course, you’ve seen a sylvinite mine.
Sylvinite is a mixture of rock and potassium-bearing salts, and its vibrant colors make the walls of this mine in Berezniki look like they’ve been covered in elaborate tapestry.
The rock-salt mixture has been found on every continent except Australia and Antarctica. The deposits are in places that millions of years ago were covered by seas and oceans that left behind layers of salt.
The potassium in sylvinite has been a popular addition to fertilizer since the 19th century and has had huge effects on the global food trade. Potassium makes the skin of some fruits thicker, and without it, many mangoes and bananas wouldn’t survive being shipped overseas.
Follow Becky Little on Twitter.
These photos were originally published in the Russian edition of National Geographic magazine.