The Raiders of Atlantis (1983)

(aka) I predatori di Atlantide .

A team of scientists working to raise a sunken Russian nuclear submarine on an ocean platform off the coast of Miami, Florida, unearth an ancient Atlantean relic from the sea floor and bring in an expert to make some sense of it. But while attempting to raise the sub, radioactive leakage from its missles triggers the re-emergence of Atlantis, and the resulting tidal wave destroys the platform and leaves only a small group of survivors.