Ancient Egypt

Underwater archaeologists working off the Egyptian coast announced in 2000 the discovery of an entire submerged ancient Egyptian city. When discussing the find with the media at a news conference in Alexandria, the French marine archaeologist, Franck Goddio, revealed the first evidence of what was believed to be the ancient city of Herakleion (or Heracleion).

A lost world

His divers had located a lost world of temples, houses, and colossal statues. Numerous artefacts were also recovered from Herakleion's sister city of Menouthis. It was still not known at the time what had destroyed the cities more than a thousand years ago.

The remains of Herakleion were found less than ten metres beneath the surface of the Mediterranean. Dating from before the fifth century BC, with legendary origins as far back as the twelfth century BC, the city is believed to span the Pharaonic, Ptolemaic, and Byzantine eras.

The city was once at the mouth of the Nile, built on adjoining islands in the delta and intersected by canals. Now it lies in Alexandria's Aboukir Bay. Historians always knew of its existence, along with its sister city, Menouthis, which was rediscovered late in the twentieth century, but no one had ever seen the evidence.

'City of sin'

Herakleion was a city which grew rich from taxes and was once renowned for its lax morals. Curiously, this so-called 'city of sin' was also a place of pilgrimage for people from all over the eastern Mediterranean. Here, people worshipped the Pharaonic cult of Isis well into the first millennium AD.

Yet something happened which wiped out the city.

One theory is that an earthquake shifted the angle of the Nile, causing this city of several thousand inhabitants to sink beneath the water. The city had been built on the Nile silts. Following the initial earth tremors, and probably the earthquake itself, the silts could have suffered liquefaction, causing them to shift and slide, and the city along with them.

As more and more artefacts could be raised from the sea in subsequent years, it was a mystery which scientists were hoping to solve. But there was other work going on too. Mr Goddio's divers used electronic sensors to locate the ruins of another city, this one believed to be around two thousand years old.

Technological advances

This was the ancient city of Alexandria, founded in the fourth century BC and now proving to be a treasure trove of lost civilisation.

However, it was only much more recently, with the advent of advanced underwater technology, that the full extent of its ancient ruins could be brought to the public eye. Mr Goddio's team explored the shallow waters around Alexandria for several years.

In 1998, they recovered a granite sphinx which was believed to have been modelled on Cleopatra's father. A statue of the goddess Isis was also discovered (both are shown in the sidebar photographs).

As if that wasn't enough, in 1999 they excavated the remains of the fleet of Napoleon Bonaparte, which was sunk by the British under Admiral Nelson in 1798. The defeat essentially marked the end of Napoleon's quest to conquer British India... but that's another story.

Some images and original text copyright © BBC or affiliates. Reproduction is made on a 'fair dealing' basis for the purpose of disseminating relevant information to a specific audience. No breach of copyright is intended or inferred.