Experts are using the latest tech to investigate Pavlopetri in Greece, the world's oldest sunken city, and their new discoveries are revealing the dark secrets of a strange world mysteriously lost to the ocean almost four thousand years ago.

Brand-new discoveries are revealing the secrets of the cataclysmic volcanic eruption that destroyed Pompeii two thousand years ago, and using the latest tech, experts are unearthing treasures that challenge everything we know about this strange place.