Underwater Worlds (S02E03)

Across the planet, hidden beneath the waves are ancient cities that raise questions about lost cultures or potential extraterrestrial encounters. The legendary Atlantis may hold clues to a forgotten alien metropolis. In Peru's Lake Titicaca, recently uncovered temples lend credence to local myths of an underwater UFO hub. Ancient Indian scriptures, called Sangams, tell of submerged cities where humans and aliens coexisted millennia ago. Who constructed the 600-foot stone structure off Japan's coast, which could be older than the Egyptian pyramids by several thousand years? Might the secrets of ancient alien interactions be concealed in the ocean's depths?