The legendary lost city of Atlantis has never been found, but there are several other sunken civilizations that were once thriving metropolises. Some met their watery fates due to natural disasters and at least one was purposefully submerged. Here's a look at the underwater cities and the treasures they took to the bottom of the sea.

Heracleion

Camera: Roland Savoye ©Franck Goddio/Hilti Foundation

French archaeologist Franck Goddio was searching for 18th-century French warships off the coast of Egypt in the Mediterranean Sea when he found something much more spectacular, reports Atlas Obscura. Goddio saw a gargantuan face in the watery depths and realized he had happened upon the lost city of Thonis-Heracleion (the Egyptian and Greek names of the city).

The city was once one of the most powerful port cities in the world, controlling all trade coming into Egypt. But after various natural catastrophes, it sunk sometime in the 8th century. Since Goddio's discovery in 2000, 64 ships, 700 anchors, 16-foot statues, gold coins and the remains of a temple to the god Amun have been found among the underwater ruins.

Canopus

Camera: Roland Savoye ©Franck Goddio/Hilti Foundation

Also excavated by Goddio, this ancient Egyptian town was submerged for more than 1,000 years. Some researchers believe the natural disasters that sent Canopus and neighboring Heacleion to their watery graves were sudden. Jean-Daniel Stanley, a geoarchaeologist with the Smithsonian Institution in Washington, D.C., believes a major flood of the Nile was to blame. The flood, he says, triggered the sinking of the cities by turning the ground beneath them into liquefied mud.

The collapse was unexpected and catastrophic, Stanley told National Geographic. "We can tell," he said, "because in both places we've found gold and jewelry, which, if there had been time, people would have taken with them when fleeing."

Phanagoria

phanagoria excavations Phanagoria is often referred to as the 'Russian Atlantis.' (Photo: Janmad/Wikipedia)

The largest ancient Greek city on Russian soil, Phanagoria was a thriving trade city. It survived for more than 15 centuries, reports The International Review of Ancient Art & Archaeology Magazine, and withstood wars and invasions. Although other towns were built on its ruins, eventually more than one-third of the city became submerged.

Often referred to as the "Russian Atlantis," Phanagoria was first explored in the 18th century but was not excavated in earnest until the 1930s. Recent finds have included coins, vases, pottery, terracotta figurines, jewelry and metal items.

Pavlopetri

pavlopetri The ruins of Pavlopetri are a short distance under the surface of the water on Vatika Bay in Greece. (Photo: World Monuments Fund)

Estimated to be about 5,000 years old, the sunken Greek settlement of Pavlopetri dates back to the time of Homer. Although discovered almost 50 years ago, it wasn't until 2009 that researchers got serious about unearthing its treasures, reported the Guardian.

"There is now no doubt that this is the oldest submerged town in the world," said Dr. Jon Henderson, associate professor of underwater archaeology at the University of Nottingham. "It has remains dating from 2800 to 1200 BC, long before the glory days of classical Greece. There are older sunken sites in the world, but none can be considered to be planned towns such as this, which is why it is unique."

Port Royal, Jamaica

Port Royal sunken city Many of the treasures of Port Royal have yet to be uncovered. (Photo: Jamaica National Heritage Trust)

This land of privateering and notorious pirates was once known as the "wickedest city on Earth." It was centered on the slave trade and the export of sugar and raw materials and with success, the land became a place of opulence and decadence. However, according to UNESCO, "At the height of its glittering wealth, on June 7, 1692, Port Royal was consumed by an earthquake and two thirds of the town sank into the sea." In just a few minutes, nearly 2,000 people died, and 3,000 people later died from injuries. People blamed the incident on divine retribution for the town's sinful ways.

The only sunken city in the Western Hemisphere, Port Royal offers a unique viewpoint in that it has buildings both on land an in the water. And, because the disaster happened so suddenly, it preserved a moment in time, with lots of details of everyday life.

Alexandria

diver eyes a sphinx uncovered in Alexandria A diver eyes a sphinx made of black granite. The face of the sphinx is believed to represent Ptolemy XII, father of the famous Cleopatra VII. The sphinx was found during excavations in the ancient harbor of Alexandria. (Photo: ©Franck Goddio/Hilti Foundation, photo: Jérôme Delafosse)

The city of Alexandria was founded by Alexander the Great in 331 B.C. Filled with palaces and temples, Alexandria's architecture and culture overshadowed even the great city of Rome, writes Goddio. The city was a cultural, religious, political and scientific capital and eventually included the royal quarters where Queen Cleopatra, Julius Caesar and Marc Antony would stay.

But disaster hit, and a combination of earthquakes and tidal waves sent much of Cleopatra's palace and parts of the city's ancient coastline into the sea. For more than 1,200 years, the ruins remained untouched on the seabed. Goddio and his team of archaeologists and historians have used advanced technology to explore the area since 1992. They have excavated what has been called one of the richest underwater archaeological sites in the world. A monument excavated on the Island of Antirhodos in the eastern harbor of Alexandria may have stood there during Cleopatra’s reign.

Shicheng City

Shicheng City Shicheng City was flooded on purpose to make room for a hydroelectric power station. (Photo: Aavindraa/Wikimedia Commons)

In 1959, the city of Shicheng (which means "lion city") was intentionally submerged to make room for the construction of a hydroelectric power station. The city was 1,339 years old. The more than 300,000 people who had to be relocated could trace their home back for generations. The well-preserved city with many statues and five entry gates is a time capsule of the period and is open to divers.

Mary Jo DiLonardo Mary Jo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.