In today’s Discovery: Has science solved one of history’s greatest adventure mysteries? Plus, a big (big!) chalk drawing, and why these sharks can live for centuries. 

But first: What secrets lie in this frozen labyrinth? 

PHOTOGRAPH BY FRANCOIS-XAVIER DE RUYDTS 

Near the peak of Mount Rainier, tucked within the majestic volcano’s east crater, lies a network of dark and vast ice caves. What secrets lie in this icy labyrinth? To find out, scientists had to venture into the frozen mouth of a volcano—14,000 feet above sea level.

More discoveries:
— Chile’s glaciers are dying. You can actually hear it. 
— 4.5 billion years ago, another planet crashed into Earth. We may have found its leftovers.

PHOTOGRAPH BY ROBB KENDRICK, NAT GEO IMAGE COLLECTION

PHOTOGRAPH BY 4 SEASON BACKPACKING, SHUTTERSTOCK 

No one is sure how long it’s been there, but in England’s rural Cerne Valley, a 180-foot-high chalk figure dominates a steep hillside. The figure is of a naked man brandishing a club and has since baffled those who sought to explain it. But recent research may reveal more about its significance—and its long history.

BEFORE YOU GO: These are the best stargazing sites in North America.

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