Ars:
Further investigation led to the conclusion that this was a manmade megastructure built some 11,000 years ago to channel reindeer herds as a hunting strategy. Dubbed the "Blinkerwall," it's quite possibly the oldest such megastructure yet discovered, according to a new paper published in the Proceedings of the National Academy of Sciences—although precisely dating these kinds of archaeological structures is notoriously challenging.
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A similar submerged stone-walled drive lane, known as "Drop 45," is located in Lake Huron in the US; divers found various lithic artifacts around the drive lane, usually in circular spots that could have served as hunting blinds.