In today’s Escape: This missing Wonder of the World was impressive enough to inspire countless imitations. Plus, the real reason the U.S doesn’t use the metric system and why cracking your knuckles is so satisfying.

But first: Even elephant moms need help. 

 PHOTOGRAPH BY DAVID CHANCELLOR, NAT GEO IMAGE COLLECTION 

Years ago, researchers noticed a 10-year-old African elephant had disappeared from her herd. A month later she returned with two unrelated females in tow—one with a newborn calf. What happened next was remarkable, and shines a light on a fascinating part of elephant society.

More stories:
— The secret to mindful travel? Forest bathing.
— Why your dog helps you relax more than your friends do

PHOTOGRAPH BY HANS NELEMAN, GETTY IMAGES

PHOTOGRAPH BY ALICE ZOO

This miracle plant was used to cure diseases and make food tastier—until Emperor Nero allegedly consumed the last stalk. But now, a Turkish researcher thinks he’s found a botanical survivor. What is this plant’s name? 

A. Orris
B. Chickory
C. Silphion
D. None of the above

BEFORE YOU GO: Move over, honeybees—here’s why America's 4,000 native bees need a day in the sun.

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