You Won't Believe These Astounding Nature Photos Are Real

Mammatus Clouds

Mammatus clouds, or mammary clouds, earned their name because they resemble udders. These clouds often appear along with severe stormy weather or tornados; pilots avoid them due to turbulence. They are formed by cold air sinking in pockets, causing their unique shape as hot air rises in tandem. These clouds were first sighted in 1894. They may be pretty, but they're definitely bad news.

The More You Know

Pittsburgh is the only city where all three major sports teams share the same colors.
After Hitler ordered the deportation of Denmark's Jewish population, Danish citizens organized a massive evacuation of the Jews to neutral Sweden, despite the risks. In the end, 99% of Danish Jews survived the Holocaust.
Martin Luther King Jr. had a C in public speaking.
The Canary Islands are named after dogs, not birds.

Post originally appeared on Upbeat News.