Scientists have discovered a stone age wall beneath the waves off Germany’s Baltic coast, which may be the oldest known megastructure built by humans in Europe. The wall, named the Blinkerwall, stretches for nearly a kilometer along the seafloor and is covered by 21 meters of water. Closer inspection of the structure reveals smaller stones positioned to connect larger boulders, suggesting intentional construction. Researchers believe it was constructed over 10,000 years ago and served as a driving lane for hunters in pursuit of reindeer herds. Further exploration of the area is planned in hopes of finding more evidence of ancient life.
https://www.theguardian.com/science/2024/feb/12/stone-age-wall-found-at-bottom-of-baltic-sea-may-be-europes-oldest-megastructure