Archaeologists have identified what may be Europe's oldest human-made megastructure, submerged 21 meters below the Baltic Sea in the Bay of Mecklenburg, Germany. This structure—which has been named the Blinkerwall—is a continuous low wall made from over 1,500 granite stones that runs for almost a kilometer. The evidence suggests it was constructed by Paleolithic people between 11,700 and 9,900 years ago, probably as an aid for hunting reindeer.