10,000-yr-old wall found under Baltic Sea said to be Europe's 'oldest megastructure'

A 10,000-year-old wall has been discovered at the bottom of the Baltic Sea, researchers said, adding that the wall might be Europe's "oldest megastructure". The structure, made of around 1,400 smaller stones and 300 larger boulders, was discovered stretching for almost a kilometre along the coast of Germany. The wall could've been used by hunters stalking reindeer herds, researchers added.