In today's Discovery: Six mystery islands that are only legend ... right? Also, 1,300 mysterious circles on the seafloor and the missing heiress in New York’s oldest cold case.

But first: Some of the world’s most significant archaeological findings.  

PHOTOGRAPH BY O. LOUIS MAZZATENTA 

Here's what a world without archaeology would look like: A Chinese emperor’s terra-cotta army would still be hidden beneath the dark soil of a farmer’s field. No Maya cities looming out of dense jungle. No luxurious Pompeii. Revisit the archaeological discoveries that changed our understanding of who we are and where we came from. 

More discoveries:
— See 100 of the world’s most important archaeological treasures
— The missing heiress at the center of New York’s oldest cold case  

PHOTOGRAPH BY BETTMANN, CONTRIBUTOR, GETTY IMAGES

PHOTOGRAPH BY LAURENT BALLESTA

When 1,300 eerily perfect circles were discovered on the bottom of the Mediterranean Sea, theories swirled about what they could mean. Were they formed by a mysterious organism? Unused World War II bombs? Well, after years of underwater research, we may finally know.

BEFORE YOU GO: See 14 iconic beaches you should visit in your lifetime. 

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.