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4 weeks ago
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From its founding by Alexander the Great to the birth of Cleopatra, this ancient city has been the site of some of history's most important moments.
But now, scientists warn that Alexandria is sinking into the sea thanks to rising sea levels.
A new study shows that the 2,300-year-old port city is experiencing a 'dramatic surge' in building collapses.
The researchers warn that the city - once home to two wonders of the ancient world, the Great Library of Alexandria and the Lighthouse of Alexandria - is now gradually disappearing.
In the last decade alone, the rate of collapses has accelerated from one per year to an 'alarming' 40 per year as saltwater creeps further up beneath the city's foundations.
Over the last 20 years, 280 buildings have been destroyed by coastal erosion with 7,000 more now at risk of collapsing in the future.
Lead author Sara Fouad, a landscape architect at the Technical University of Munich, says: 'For centuries, Alexandria's structures stood as marvels of resilient engineering, enduring earthquakes, storm surges, tsunamis and more.
'But now, rising seas and intensifying storms — fueled by climate change — are undoing in decades what took millennia of human ingenuity to create.'
These images show the same locations 90 years apart, revealing just how far the coastline has retreated due to rising sea levels
Founded by Alexander the Great in 331 BC, Alexandria was once the biggest city on Earth and was one of the most important locations in the ancient world.
Known as the 'Bride of the Mediterranean', the city's position on the coast made it an important hub of trade and shipping connecting the Middle East and Europe.
However, the proximity to the water that once made the city prosperous now threatens to destroy it as the sea rapidly encroaches.
As the planet warms due to the buildup of greenhouse gases in the atmosphere, the ocean's average temperature increases.
As the water warms it also expands and, combined with added freshwater from rapidly melting ice sheets, pushes up the global sea level.
According to the National Oceanic and Atmospheric Administration (NOAA), global sea levels have risen between 20 and 23 centimetres since 1880, with 10 cm of that rise coming since 1993 alone.
A recent study from the Nanyang Technological University (NTU), Singapore, predicted that global sea levels could rise by a staggering 6.2ft (1.9 metres) by 2100 if carbon dioxide (CO2) emissions continue to increase.
The researchers combined satellite imagery with historical maps to see how fast the city's coast had vanished since the 1880s.
The ancient city of Alexandria (pictured) is now at risk of disappearing into the sea as rising sea levels trigger a 'dramatic surge' in building collapses
Satellite imagery and historical images reveal that the shoreline has retreated tens of metres from its position in the 1880s (shown as a black line) to where it is today (shown in red). Some parts of the city have lost 3.6 metres of coast each year
This revealed that Alexandria's shoreline has moved inland by tens of metres over the last few decades, with some areas retreating by 3.6 metres per year.
Study co-author Dr Essam Heggy, a water scientist at the University of Southern California, says: 'We are witnessing the gradual disappearance of historic coastal cities, with Alexandria sounding the alarm. What once seemed like distant climate risks are now a present reality.'
But sea level increases do not need to be dramatic in order to have disastrous consequences.
Dr Heggy, a water scientist at the University of Southern California, says: 'Our study challenges the common misconception that we'll only need to worry when sea levels rise by a meter.'
Sea level increases of just a few centimetres increase the risk of flooding and, critically, allow saltwater to penetrate further into coastal cities.
As the groundwater level rises, it comes into contact with building foundations, and the resulting saltwater intrusion undermines structures long before they ever come into direct contact with the sea.
The researchers took soil samples around the city to look at the 'chemical fingerprint' associated with saltwater intrusion.
Co-author Professor Ibrahim Saleh, a soil scientist from Alexandria University, says: 'Our isotope analysis revealed that buildings are collapsing from the bottom up, as seawater intrusion erodes foundations and weakens the soil.
Even in districts up to 2km from the coast, there has been an 'alarming' increase in building collapses. This is because a small rise in sea levels has allowed saltwater to reach the foundations of buildings much further inland
This map shows areas of building collapses in orange. In these areas, chemical analysis showed that saltwater infiltration had led to soil relaxation (shown top left), weakening the ground beneath the structures and leading to their collapse
'It isn't the buildings themselves, but the ground underneath them that's being affected.'
This has led to the collapse of hundreds of buildings located over a kilometre from the coastline.
Worryingly, the researchers point out that these problems are not unique to Alexandria and could affect coastal cities all over the world.
A recent NASA study found parts of California, including San Francisco are literally 'sinking' into the ocean faster than the sea level itself is rising.
As the landslips lower towards sea level, saltwater is able to penetrate further inland and undermine more buildings.
To address these issues, the researchers suggest a number of possible solutions, including building sand dunes along the coast, elevating buildings, or relocating people in the most vulnerable areas.
Dr Heggy concludes: 'Historic cities like Alexandria, which represent the cradle of cultural exchange, innovation and history, are crucial for safeguarding our shared human heritage.
'As climate change accelerates sea level rise and coastal erosion, protecting them isn't just about saving buildings; it's about preserving who we are.'
WHO WAS ALEXANDER THE GREAT?
Alexander III of Macedon was born in Pella, the ancient capital of Macedonia in July 356 BC.
He died of a fever in Babylon in June 323 BC.
Alexander led an army across the Persian territories of Asia Minor, Syria and Egypt claiming the land as he went.
Alexander III of Macedon was born in Pella, the ancient capital of Macedonia in July 356 BC
His greatest victory was at the Battle of Gaugamela, now northern Iraq, in 331 BC, and during his trek across these Persian territories, he was said to never have suffered a defeat.
This led him to be known as Alexander the Great.
Following this battle in Gaugamela, Alexander led his army a further 11,000 miles (17,700km), founded over 70 cities and created an empire that stretched across three continents.
This covered from Greece in the west, to Egypt in the south, Danube in the north, and Indian Punjab to the East.
Alexander was buried in Egypt, but it is thought his body was moved to prevent looting.
His fellow royals were traditionally interred in a cemetery near Vergina, far to the west.
The lavishly-furnished tomb of Alexander's father, Philip II, was discovered during the 1970s.
