Towering over Alexandria, the vibrant Mediterranean port and capital of Ptolemaic Egypt, an enormous lighthouse was a symbol of the ambition of the Hellenistic age, a 140-metre skyscraper of granite and limestone that Gregory of Tours, a sixth-century CE Gallic bishop, deemed the seventh wonder of the ancient world. Its powerful beam was a nightly promise of safety for mariners approaching the treacherous coastline, and the structure was second in height only to the Great Pyramid of Giza, commonly accepted as the first wonder of the ancient world and the only one that survives.
For nearly 1,600 years, the lighthouse, known as the Pharos of Alexandria, stood on an island at the entrance to the city’s eastern harbour as a sentinel defiant against time and nature, shrugging off dozens of earthquakes. But even monumental ingenuity has its limits; in 1303 CE, a doozy of a tremor caused a tsunami so intense that it left the structure in shambles. Another quake, 20 years later, brought the rest crashing down, a tumble of statues and masonry eventually swallowed by the ever-rising sea.
“The architectural fragments lie scattered over 18 acres underwater,” said Isabelle Hairy, an archaeologist at the National Centre for Scientific Research in France and the Centre for Alexandrian Studies in Egypt. “The visibility is extremely bad, the seabed is uneven and there are no clear layers of sediment.”
For the past four years, Hairy has led the Pharos Project, guiding an elite squad of historians, numismatists, architects and graphics programmers to reconstruct the ancient lighthouse as a comprehensive digital twin. Having so far analysed roughly 5,000 blocks and artefacts on the sea bottom, the team is reverse-engineering the ancient structure from its 14th-century collapse.
Projection of power
After Alexander the Great, a ruler of Macedonia and its vast empire, died suddenly in 323 BCE, his boyhood companion Ptolemy took control of Egypt as its governor. In 305 BCE, he appointed himself pharaoh, Ptolemy I Soter (the Saviour).
To transform the city into the centre of the cult of Alexander the man-god, Ptolemy commissioned a monumental lighthouse or the Pharos. Despite limited physical evidence and clashing historical accounts, scholars generally agree that the Pharos was a majestic three-tiered tower resembling a wedding cake. The square base, sprawling over 340 metres, served as a fortified hub for fuel and livestock, housing a garrison and apparatuses for lifting food and supplies.
Rising from its immense foundation, the structure narrowed into an eight-sided marvel punctured by open windows and crisscrossed by internal spiral stairs.
This octagonal heart, stretching nearly 61 metres into the sky, was the work of Sostratus of Cnidus, a visionary Greek builder from what is now southwestern Turkey. By shaping the second story as an octagon, he honoured the eight winds of the sea.
The signalling lantern burned in the crowning, circular tier, probably in an open-air setup exposed to the Mediterranean winds rather than encased in glass. Above it all, a grand 15-metre statue of a god, watched over the port. Some authorities interpret this top section differently — perhaps it was a fourth, subdivided layer that housed the beacon and statue pedestal separately.
Resurfacing relics
Reduced to a shell by the 1323 earthquake, the lighthouse lay neglected until 1480, when Sultan Qaitbay repurposed its ruins to build a citadel that still guards the shore. The lighthouse found a second life in this fortress, but much of ancient Alexandria — including the royal palace and Alexander the Great’s tomb — sank beneath the waves as a result of geological shifts.
Hints of this sunken kingdom surfaced in 1916 when reports of underwater statues began to emerge. Following a brief Unesco scouting mission in 1968, the site was finally brought to light in 1994 through the mapping efforts of French archaeologist Jean-Yves Empereur and his team from the Centre for Alexandrian Studies.
Eighty-five feet down, divers discovered a stunning trove of artefacts, including 30 sphinxes, a 63.5-tonne door frame, another door frame 4.8 metres high and a half-dozen elegant columns from the reign of Ramses II in the 13th century BCE.
The most striking find was a gigantic statue, almost certainly of a pharaoh, similar to one of a queen in the guise of Isis that the Egyptian navy had raised in 1961. It is now believed that the pair represent Ptolemy I and his wife, Berenice I.
Last summer, working with the Egyptian Ministry of Tourism and Antiquities, the team used a barge-mounted, high-capacity crane to hoist 22 granite blocks, some weighing up to 72.5 tonnes, from the seafloor. The operation recovered more than 100 submerged relics.
Once safely brought to the surface, these colossal components underwent high-resolution scanning by engineers from La Fondation Dassault Systèmes, which documented and virtually repositioned them to reimagine the Pharos’ lost design without putting the original stone at risk. After the blocks were measured, they were returned to the sea for long-term preservation.
Old assumptions
Many experts remarked that the Pharos Project had significantly advanced the modern understanding of the lighthouse by moving from speculative sketches to empirical, physical analysis.
Among other insights, it has revealed that the structure was assembled using advanced interlocking techniques rather than relying solely on mortar. “The clamps help explain how such a massive structure was erected in such a short time,” Hairy said. He estimated that the project was still generations from completion, but the mission has already defied expectations.
NYTNS
