The origins of one of the America’s oldest unsolved mysteries can be traced to August 1587, when a group of about 115 English settlers arrived on Roanoke Island, off the coast of what is now North Carolina. Later that year, it was decided that John White, governor of the new colony, would sail back to England in order to gather a fresh load of supplies. But just as he arrived, a major naval war broke out between England and Spain, and Queen Elizabeth I called on every available ship to confront the mighty Spanish Armada. In August 1590, White finally returned to Roanoke, where he had left his wife and daughter, his infant granddaughter (Virginia Dare, the first English child born in the Americas) and the other settlers three long years before. He found no trace of the colony or its inhabitants, and few clues to what might have happened, apart from a single word—“Croatoan”—carved into a wooden post.

Investigations into the fate of the “Lost Colony” of Roanoke have continued over the centuries, but no one has come up with a satisfactory answer. “Croatoan” was the name of an island south of Roanoke that was home to a Native American tribe of the same name. Perhaps, then, the colonists were killed or abducted by Native Americans. Other hypotheses hold that they tried to sail back to England on their own and got lost at sea, that they met a bloody end at the hands of Spaniards who had marched up from Florida or that they moved further inland and were absorbed into a friendly tribe. In 2007, efforts began to collect and analyze DNA from local families to figure out if they’re related to the Roanoke settlers, local Native American tribes or both. Despite the lingering mystery, it seems there’s one thing to be thankful for: The lessons learned at Roanoke may have helped the next group of English settlers, who would found their own colony 17 years later just a short distance to the north, at Jamestown.