During a routine treasure hunt in 2011, the Ocean-X team, which uses sonar to find sunken shipwrecks, scanned an anomaly on the seabed of the Baltic Sea.
The Ancient Nerds DAO has published an article on the subject and is celebrating by giving away this exclusive NFT Collection.
Learn more about the Baltic Sea Anomaly:
https://medium.com/@ancientnerdsdao/the-baltic-sea-anomaly-ac435332954a