Once-imperious early 20th-century buildings stand in glorious dilapidation along the waterfront corniche and twisting backstreets.
Overstaffed, high-ceilinged coffee houses like the Trianon regret the passing of the Armenian cotton traders, Greek shipping agents and European aristocrats who were once their patrons.
Any visitor wanting to revel in Alexandria's decayed grandeur should stay (or on a tighter budget, take mint tea) at the Windsor Palace or the Cecil, both on the corniche. These offer ornate caged lifts, decor that celebrates a lost colonial world and bright views of the blue-green sea, to a contemporary soundtrack of traffic and calls to prayer.
Alexandria has few true monuments. It bears little resemblance to the white marble city where first Julius Caesar, then Mark Anthony lusted after their hostess. There are Greek and Roman remnants, some evocative catacombs, and mosques that are nothing compared with Cairo's.
The building most likely to quicken the pulse is only five years old: the US$220 million library, a disc sliding down to the seafront, designed by Norwegian architects Snohetta.
But, under the sea, it's another story. Just in front of the corniche, less than 20 metres under the surface of the Mediterranean, lie the ruins of the ancient royal city: the lighthouse that was one of the world's Seven Wonders and the palace where Anthony and Cleopatra lived out their last days.
These were subsumed by earthquake and subsidence 1600 years ago, then catalogued by divers from the 1960s onwards.
Dr Ashraf Sabry owns Alexandra Dive, the only operator permitted to take tourists diving here.
"My background helped," admits the native Alexandrian and son of a submarine commander.
"We all knew it was here, where we spear-fished. Of course, the French did their usual thing and demanded it be called a discovery."
Floating in the Mediterranean's half-light, gliding over fields of fallen columns, it's easier to recreate these ancient times than it would be in a museum. No glass case prevents you from touching the massive blocks of red granite from up the Nile at Aswan, which once formed part of the lighthouse, its fire visible for 30 miles.
Where nature has reclaimed the site, small nervous fish must be shooed away and seaweed rubbed off to make out a faint Greek inscription or to appreciate the curve of an amphora at the site of the old docks.
My diving guide, Said, uses ingenious gestures to indicate which items he believes to be of the Pharaohs, which Roman, or to alert me to a man-sized sphinx crouching in the gloom.
There are aspects missing from the palace which you must recreate in your mind: onyx floors, ivory furniture, walls reportedly of tortoise shells encrusted with emeralds.
Some of the finds, such as golden jewellery and the huge head of Cleopatra's nemesis, Octavian, have been hauled up and sent to museums. But in Cairo, Dr Zawi Hawas, head of the Supreme Council for Egyptian Antiquities, says the rest will remain in situ and with Unesco's help he plans to create viewing tunnels for unwilling divers.
"Water," he says, "can help us smell the past."
Alexandria does still hold some of the capricious charm that Durrell breathlessly described as "scheming, malevolent, deeply beguiling".
But if you have the time and means, you should follow in the footsteps of Alexander himself, who turned west 300 miles across the desert to the oasis of Siwa.
What made Siwa more than a watering hole in antiquity was its renowned oracle, who delighted Alexander by confirming he was the son of the great god Amen.
Visiting the chamber where the great statue used to stand, you can see a side tunnel from which canny priests might have imitated the oracle's voice. Nearby, the core of Siwa is a ruined mud-built citadel, destroyed by the shock of rain in 1927.
Since then something more welcoming has arisen in the form of the Adrere Amellal desert retreat.
Nestled beside a starkly beautiful escarpment in its own oasis, and to the sound of only desert wind and birdsong, it offers an understated luxurious hospitality. The adobe, palmwood and translucent saltstone of its construction are local, as are the dates, honey and vegetables that go into the exceptional food.
Mounir Naemattala, for whom the Amellal is a labour of love, also campaigns for the protection of the local environment and Berber crafts. Here you can assuage the guilt from less environment-friendly trips and take a dip in Siwa's hot springs.
The greatest surprise lies in the desert, where there are sea shells underfoot and a large petrified fish skeleton reminiscent of the German Heinkel bomber wreck we had explored in the sea at Alexandria.
The reason, of course, is that nothing stays the same.
Just as Cleopatra's palace has become a seascape, so the Sahara was once, millions of years past, itself a teeming ocean.
CHECKLIST
Accommodation: Try The Cecil Hotel, the Windsor Palace Hotel or Adrere Amellal desert resort.
- OBSERVER
