Millions of landmines remain strewn across Angola, remnants of the country’s long civil war. Remarkably, some elephants have learned to sniff out and avoid these hazards, and even alert an entire herd to the danger. Intrigued, the U.S. Army is now testing the ability of elephants to detect chemicals found in landmines—and they’re passing with “flying colors.”

Top image: Reuters/Siphiwe Sibeko