Divers were exploring a section of seabed in September 2018 off the coast of Portugal, not far from the country’s main port and capital Lisbon. As on any dive, they were hoping to find something interesting. But what they did find blew “interesting” right out of the water.
In fact, the divers are part of a team that’s been working for the past 10 years with the Cascais Underwater Archaeological Chart Project. They’ve been mapping the seabed off the pretty Portuguese fishing and resort town of Cascais, which is some 15 miles to the west of Lisbon.