In today’s Escape, what is it called when you aren’t an introvert or an extrovert? Plus, why curly hair was an evolutionary advantage, the reason your mental map of the world is (probably) wrong, and the 10 most popular national parks.

But first: See these snoozing polar bears enjoying summer's warmth. 

PHOTOGRAPH BY MARTIN GREGUS, JR. 

When you think of polar bears, you probably picture them trudging through ice and snow. But photographer Martin Gregus Jr. wanted to capture a softer side to the world’s largest terrestrial predator. What he found were bears enjoying their summer by sunbathing, swimming, wrestling over rocks—and sleepy enough to take a snooze in a bed of flowering plants.

More animal stories:   
— Scientists may finally know why these birds form mesmerizing clouds  — See what happens when a polar bear finds a camera

Thanks for reading. In celebration of Earth Day, please enjoy 50% off Nat Geo Digital, now $19/yr!

PHOTOGRAPH BY WOLFGANG KAEHLER, LIGHTROCKET/GETTY IMAGES 

PHOTOGRAPH BY CAMERON STRAND

This June, the legendary runner Faith Kipyegon is aiming to do something that sports scientists once considered impossible: become the first woman to run a mile in less than four minutes. We went inside her Kenyan training camp to understand how she’s pushing the limits of human performance.

BEFORE YOU GO: Looking to enjoy the weather? Here are the 10 most popular national parks.

Today’s newsletter was edited and curated by Jennifer Baik and produced by Amanda Williams-Bryant. Thanks for reading! Did someone forward this to you? Sign up for all our newsletters here.