Exploring Cleopatra's Sunken Palace

A diver inspects a quartzite block with an engraving of a Pharaoh (indicated by hieroglyphic inscriptions as Seti I, father of Ramses II) on the seabed of the harbor of Alexandria, Egypt. An international team of divers led by French underwater archaeologist Franck Goddio is using advanced technology to explore the submerged ruins of a palace and temple complex from where Queen Cleopatra ruled.

Alexandria's Royal Quarters - ports, a cape and islands full of temples, palaces and military outposts - simply slid into the sea after cataclysmic earthquakes in the fourth and eighth centuries. The harbor was abandoned and left untouched as an open bay, while modern construction went forward in the Western Harbor, leaving the ancient Portus Magnus undisturbed. Since the mid-1990s, using ancient maps and advanced technology, Franck Goddio and his team of archaeologists and historians have charted the entire harbor, including its remains of palaces and temples, as well as the famous royal island of Antirhodos.

An archaeological diver plunges into the sea from the Princess Duda research boat anchored in the harbor of Alexandria, Egypt, Tuesday, May 25, 2010. The archaeologists are painstakingly excavating one of the richest underwater archaeological sites in the world and retrieving stunning artifacts from the last dynasty to rule over ancient Egypt before the Roman Empire annexed it in 30 B.C.

AP/Franck Goddio & Hilti Foundation, Christoph Gerigk

Since the early 1990s, the topographical surveys have allowed the team, led by French underwater archaeologist Franck Goddio, to conquer the harbor's extremely poor visibility and excavate below the seabed.

An archaeologist positions a grid to take precise measurements underwater.

This colossal granite head discovered on the ancient coastline facing Antirhodos Island has been identified as Caesarion, son of Cleopatra and Caesar. The original statue would have been as tall as five meters.

Sediment helped preserve many of the artifacts found, including this gold ring (top); below, a Sphinx found on Antirhodos Island.

French underwater archaeologist Franck Goddio shows a recently-excavated bronze cult statue found in the Temple of Isis, in the harbor of Alexandria, Egypt, Tuesday, May 25, 2010.

The bronze figure, found in the Temple of Isis, sits in a bath of fresh water to desalinate it.

Recently excavated artifacts are shown onboard the Princess Duda research boat, anchored in the harbor of Alexandria, Egypt, Tuesday, May 25, 2010. The divers have uncovered everything from coins and everyday objects to colossal statues of Egypt's rulers.

This recently-excavated statuette is of a boy Pharaoh, dating from the 4th or 5th century B.C.

Recently excavated pottery is shown on board the Princess Duda research boat.

These recently recovered stone plates lie in a bath of fresh water to desalinate them, on board the Princess Duda research boat.

Goddio, who has spent two decades searching for shipwrecks and lost cities below the seas, says of Alexandria, "It's a unique site in the world."

A member of the crew of the Princess Duda research boat stands next to the drying wetsuits of divers as it lies anchored in the harbor of Alexandria, May 25, 2010.

Last December a sunken red granite tower — part of a pylon of the Isis temple — was lifted out of the Mediterranean off the eastern harbor of Alexandria.

The granite tower is to be the centerpiece of the planned Underwater Museum here.

Egypt hopes the planned museum will draw tourists to its northern coast, often overshadowed by hotspots such as Luxor, the Giza pyramids and Red Sea beaches.

By CBSNews.com producer David Morgan

The Franck Goddio Society