For thousands of years that human civilization has spread throughout our blue planet, cities have come and gone. Hidden relics of the past 6 millennia have been discovered all over the world, many of which rest at the bottom of our oceans. What led to the sinking of these once great cities varies, though many of them remain intact enough to be identifiable. Of the many underwater ancient cities to have been discovered in waters connected to the ocean, there is Heracleion in the Abu Qir Bay in Egypt, Port Royal in Jamaica, Baiae, a city in ancient Italy in the Gulf of Naples, and Pavlopetri, that lay off the southern coast of Greece. Despite being millennia old, artifacts of these cities have survived.