In today’s Discovery: An overlooked object in a German museum changes the history of the color blue, what to know about predicting the northern lights, and newly found rock art is evidence humans might have thrived in a surprising place. Plus, we added audio to our story about ancient “hobbit” humans who remain a mystery. 

But first: Bob Ballard ventured to the depths of Guadalcanal to rediscover vessels lost in World War II.

Iron Bottom Sound got its nickname because more than a hundred warships were sunk there during World War II. Yet, at a depth of around 2,000 feet, they remain elusive as they are much too deep for human divers to reach. National Geographic Explorer-at-Large Bob Ballard’s new expedition used the latest underwater technology to survey 13 shipwrecks—including some that had not been found since sinking beneath the waves.

Today’s newsletter was edited and curated by Sidney Madden and produced by Amanda Petty. Did someone forward this to you? Sign up for our other newsletters here.