
For 1,300 years, the legend of a lost Egyptian city was exactly that — a legend. The earliest Greek historian, Herodotus, said the metropolis of Thonis-Heracleion derived its name from being the place where Heracles, the mythical strongman, first set foot on Egyptian soil.

And Helen of Troy — the most beautiful woman in ancient mythology — supposedly visited the place with her lover, Paris, 3,000 years ago.

But the city itself wasn’t exposed to the world until 2000, when a French archaeologist swam deep down into the Mediterranean, two miles off the Egyptian coast near the city of Alexandria.

There he found the ‘Egyptian Atlantis’, a city that for 500 years from the 7th century BC was the most important Mediterranean trading port in Egypt.

Towering: The 16ft statues of an Egyptian king and queen, pulled from the city of Thonis-Heracleion in the depths of the Mediterranean

Rescue operation: Three divers examine the underground world of treasures that was discovered at the ancient site near Alexandria

What the Frenchman found was a huge undersea world of toppled temple columns, statues of Egyptian gods and hieroglyphics etched into ancient slabs, seen only by shoals of fish for centuries.

At the end of the 2nd century BC, this thriving city was hit by a triple whammy of earthquakes, floods and geological subsidence.

Archaeologists have worked out that the earth beneath the major temples actually turned to liquid, thanks to a geological process called liquefaction, and most of the city’s glittering buildings and statues went spiralling down to the bottom of the sea.

A few hardy Christian souls clung on in the remnants of the city until it all slipped beneath the waves in about AD800.

Today, the murky waters of Abukir Bay, at the mouth of the Nile, are thick with sediment, and at first it was hard to work out what the huge chunks of stone half-buried in the seabed in 30ft of water might be.

On closer examination, they found a stupendous collection of statues of pharoahs and deities, glittering golden plates and coins, 69 shipwrecks and more than 700 anchors — all miraculously preserved in their undersea grave, safe from looters and vandals.

Discovery: The city itself wasn’t exposed to the world until 2000, when a French archaeologist swam deep down into the Mediterranean, two miles off the Egyptian coast near the city of Alexandria

Crossover: This 6ft statue of the Egyptian bull god Apis dates from the time of the Roman Emperor Hadrian - Romans often adopted local deities when colonising a new region

Worship: Archaeologists have worked out that the earth beneath the major temples actually turned to liquid, thanks to a geological process called liquefaction, and most of the city’s glittering buildings and statues went spiralling down to the bottom of the sea

Miraculous: Archaeologists found a stupendous collection of statues of pharoahs and deities, glittering golden plates and coins, 69 shipwrecks and more than 700 anchors

Ever since, some of the great treasures carved by the ancient Egyptians, and the Greeks and Romans who followed them, have been unearthed at Thonis-Heracleion. And now they are on display in a new exhibition at the British Museum in London.

Greeting you, as you enter, is a 17ft red granite statue of Hapy — Egyptian God of the Nile, whose waters swallowed up the rest of the benighted city 1,300 years ago. In his arms, the 4th century BC statue has an offering table, to hold gifts for the god whose name he bears.

Since the city was an international harbour, a huge variety of antiquities were found. They were so two-a-penny there was even a statue ‘tip’: among its many treasures is a smiling bust of the Egyptian king, Nectanebo II, who ruled Egypt in the mid-4th century BC. One sphinx plucked from the seabed presented a particularly curious riddle. Its human head was found in a temple, while its lionshaped body was discovered 650ft away.

Archaeologists think the sphinx was amputated by a passing trawler — looking for fish, not multi-million-pound antiquities.

The best of all the statues are a beautifully carved and beautifully preserved king and his queen, standing side by side, both 16ft tall. They towered over visitors at a preview of the show.

Find: Some of the great treasures carved by the ancient Egyptians, and the Greeks and Romans who followed them, have been unearthed at Thonis-Heracleion

Rising from the depths: A 17ft-high statue of the Nile god Hapy (left) was discovered in seven pieces and had to be carefully winched up from the seabed, reassembled and cleaned. Pictured, right, is an Egyptian tablet that raised new taxes

Thought to have been carved in the 3rd century BC, they guarded the entrance to the temple of Amun-Gereb — the god who granted the pharaohs their legal ‘right’ to rule Egypt.

The range of finds is staggeringly wide and exotic. A pile of 6th-century BC sarcophagi, or stone coffins, were found under 5ft of sediment. Intriguingly, they were for animals — the falcon and the ibis, the two birds venerated by the Egyptians. Just like human mummies, the birds were wrapped up in a tight cloth binding.

Some things are a bit more familiar to us.

As the saying goes, the only two things you can be certain of in this world are death and taxes — and the Egyptians were no different. One huge monument, in immaculate condition, is inscribed with what you might call tax-raising hieroglyphics.

These declare that the pharaoh Nectanebo has issued a royal decree, charging taxes on imports and exports passing through the port of Thonis-Heracleion.

The tax — 10 per cent — paid for a temple in honour of Neith, Nectanebo’s mother.

Saved from the sea: The range of finds at the ancient site is staggeringly wide and exotic, and includes artefacts from the Egyptians, the Greeks and the Romans

History: After the Greeks, the Romans came, conquering Egypt in 30 BC, when the future Emperor Augustus defeated Mark Antony and deposed his lover, Cleopatra

Our politicians are a rum lot, but they haven’t started taxing us for temples honouring their mothers. Yet.

In 332 BC, Alexander the Great conquered Egypt, turning this thriving port into a Greek city, and leaving it stuffed with Greek treasures.

After the Greeks, the Romans came, conquering Egypt in 30 BC, when the future Emperor Augustus defeated Mark Antony and deposed his lover, Cleopatra.

A statue of a priest from the Roman era was discovered still standing in the sand, clutching a jar which was sacred to Osiris, the Egyptian god of the dead.

The Romans often adopted local gods like Osiris when they set up new colonies.

All in all, you get a super-sharp picture of life in Thonis-Heracleion, across the three great civilisations of Egypt, Greece and Rome.

That is, until this bustling, metropolitan Mediterranean hub plunged into its watery grave.

For centuries this sunken treasure house slumbered beneath the hazy waters of the Mediterranean until, one extraordinary day in 2000, an archaeologist happened to come swimming by.