For more than 30 years, one of Italy’s most well-hidden archaeological treasures has been an underwater village called La Marmotta. The site, with well-preserved artifacts, was discovered in 1989 in a lake just northwest of Rome and 23 miles upstream from the Mediterranean Sea.

Found among its wooden buildings were five canoes, stretching up to 32 feet long and made from hollowed-out trees. Estimated to be 7,000 years old, the boats showed signs of being equipped with advanced maritime technology, including towing accessories and reinforcements.