Underwater Alexandria: Sunken Wonders of the Ancient World

Table of contents

1) The Sinking of Alexandria

Alexandria sits on an unstable geological foundation — a narrow strip of land between the Mediterranean and Lake Mariout, underlain by sediments that are prone to liquefaction during seismic events. Ancient writers noted periodic tremors, but it was the catastrophic earthquakes of 365 AD, 447 AD, and a prolonged series of events between the 6th and 8th centuries that proved most destructive. The 365 AD earthquake and tsunami, originating near Crete, was one of the most powerful seismic events in Mediterranean history, generating a wave that devastated coastal communities across the eastern basin.

Combined with a gradual eustatic rise in sea level over the centuries, these events caused the northern and eastern quarters of the city — including the royal Brucheion district — to subside by an estimated 6–8 metres. Entire city blocks, harbourside warehouses, temple precincts, and the royal island of Antirhodos sank beneath the waves. By the medieval period, this portion of Alexandria was effectively a ghost city beneath the sea, and its memory survived mainly in classical texts describing what had once stood there.

Geological factors behind the subsidence

Alexandria's northern districts rested on Nile delta sediments that compact over time and are highly susceptible to earthquake-induced liquefaction. This natural compaction, combined with the weight of dense urban construction and repeated seismic shocks, accelerated the slow sinking of entire city quarters into the sea over a period of several centuries.

2) The Lighthouse of Pharos

The Lighthouse of Pharos was constructed on the small island of Pharos in Alexandria's harbour during the reign of Ptolemy II Philadelphus (283–246 BC), and was completed around 280 BC. Standing at an estimated height of 100–140 metres, it remained one of the tallest man-made structures in the world for many centuries and guided mariners into the busy port of Alexandria. Ancient sources — including Strabo, Julius Caesar, and the Arab traveller Ibn Jubayr — provide vivid descriptions of a three-tiered tower crowned by a fire and a polished metal mirror that could reflect light visible from great distances.

The lighthouse survived largely intact until the 956 AD earthquake severely damaged its upper tiers. Subsequent earthquakes in 1303 and 1323 AD finally destroyed what remained of the structure. The Mamluk sultan Qaitbay later constructed a defensive fort (1477–1479 AD) directly on the lighthouse's foundations, using many of the ancient stone blocks in its construction. This means that both the ruins of the lighthouse on the seabed and the fabric of Fort Qaitbay itself are, in a very real sense, the physical remains of one of the Seven Wonders of the Ancient World.

3) Archaeological Evidence: Reclaiming the Past

In 1994, underwater archaeologist Jean-Yves Empereur and his team from the Centre d'Études Alexandrines (CEAlex) conducted a systematic survey of the seabed around Fort Qaitbay. What they discovered transformed our understanding of ancient Alexandria. Scattered across the harbour floor were hundreds of massive masonry blocks, sphinxes, obelisks, columns, and colossal statues — including a remarkable figure of Ptolemy II depicted in the traditional regalia of an Egyptian Pharaoh. The sheer scale and quality of these finds provided physical confirmation of the lighthouse's immense proportions and validated descriptions that scholars had long treated with scepticism.

Major Finds at Fort Qaitbay

Artefact Type	Approximate Count
Granite masonry blocks	Over 2,000 recorded
Sphinxes	At least 5 identified
Obelisks & fragments	Several large fragments
Colossal statues	Multiple torsos & heads

Statue of Ptolemy II as Pharaoh

Among the most significant individual discoveries was a colossal statue identified as Ptolemy II Philadelphus depicted in the style of an Egyptian Pharaoh — wearing the double crown and carrying the traditional crook and flail. This blending of Hellenistic ruler portraiture with pharaonic iconography reflects the deliberate strategy of the Ptolemaic dynasty to legitimise their rule in the eyes of both their Greek and Egyptian subjects. The statue fragment is now one of the centrepieces of Alexandria's National Museum.

Ongoing Survey Work

Since Empereur's pioneering survey, the Egyptian Supreme Council of Antiquities has collaborated with international teams to continue mapping the underwater site. Advanced techniques including side-scan sonar, photogrammetry, and 3D mapping have allowed archaeologists to construct detailed plans of the submerged ruins without extensive physical disturbance. This non-invasive approach is now the preferred methodology, ensuring the site is preserved for future generations and for the proposed underwater museum.

4) Cleopatra's Sunken Palace

In the late 1990s, French underwater archaeologist Franck Goddio and his team from the European Institute for Underwater Archaeology (IEASM) surveyed a broader area of Alexandria's Eastern Harbour, identifying the submerged royal island of Antirhodos. Ancient texts, most notably Strabo's Geography (written around 24 BC), describe Antirhodos as a small island in the inner harbour bearing a palace and a harbour of its own — a place associated with the Ptolemaic royal court and, later, with Cleopatra VII herself.

Goddio's team located the island's outline, columns, pavement slabs, and temple structures resting on the seabed at a depth of 4–8 metres. Recovered artefacts included red granite columns, statues of priests, and sphinxes bearing the cartouche of Ramesses II — brought from Upper Egypt to Alexandria and incorporated into Ptolemaic religious buildings. While no structure has been definitively identified as "Cleopatra's palace," the concentration of royal-quality architecture and artefacts on Antirhodos makes it by far the most plausible location for the queen's residence described by classical authors.

5) Key Artefacts Recovered

Decades of underwater excavation and survey have yielded a remarkable collection of objects that help reconstruct the appearance and character of ancient Alexandria. Many recovered pieces are now on display at the National Museum of Alexandria, while others remain in the sea in situ, awaiting the proposed underwater museum.

The diversity of the finds reflects Alexandria's cosmopolitan character as a city where Egyptian, Greek, and Roman traditions overlapped and merged. Pharaonic statues originally carved for Upper Egyptian temples stand alongside Hellenistic portrait busts and Roman-era architectural elements, all drawn together in a city that was simultaneously a Ptolemaic capital, an Egyptian metropolis, and a Roman provincial hub.

Highlights from the Eastern Harbour

• Colossal statue of a Ptolemaic ruler: A granite torso and head, over 4 metres tall, believed to represent a Ptolemaic king in pharaonic dress, discovered near Fort Qaitbay.
• Sphinxes with royal cartouches: Multiple granite sphinxes bearing the cartouche of Ramesses II, transported from Heliopolis or Memphis to Alexandria in antiquity to adorn the city's temples and palaces.
• Red granite obelisk fragments: Large sections of obelisks that once stood as landmarks within the city's ceremonial spaces, now lying on the harbour floor alongside the masonry of the lighthouse.

6) The Sunken Museum Project

One of the most ambitious proposals in the history of underwater cultural heritage is the plan to create an underwater museum in Alexandria's Eastern Harbour. First formally proposed in the early 2000s and championed by both UNESCO and the Egyptian government, the concept envisages a series of glass-walled tunnels and viewing platforms on the seabed that would allow visitors to walk among the sphinxes, columns, and masonry blocks in their original underwater context — rather than seeing them removed and displayed in a conventional museum setting.

The project remains in planning and feasibility stages, with ongoing debates about engineering challenges, preservation concerns, water visibility, and the significant financial investment required. Proponents argue that an in-situ underwater museum would be a world-first attraction of enormous cultural and tourism value, allowing the public to experience ancient Alexandria in an entirely new way. Environmental impact assessments and structural engineering studies have been commissioned, and the project continues to attract international interest, though a construction timeline has yet to be finalised.

7) Visiting & Diving Tips

Last updated: April 2026. Entry prices and opening hours are subject to change; verify with local authorities or your tour operator before visiting.

8) Sources & Further Reading

The following are reputable starting points used to compile the information on this page.

• Empereur, Jean-Yves. Alexandria Rediscovered. British Museum Press, 1998. — The foundational work on the 1994–1995 underwater excavations near Fort Qaitbay, with detailed photographs and site plans.
• Goddio, Franck & Clauss, Manfred (eds). Egypt's Sunken Treasures. Prestel, 2006. — A comprehensive illustrated catalogue of the IEASM's Eastern Harbour and Canopus discoveries.
• Clayton, Peter A. & Price, Martin J. (eds). The Seven Wonders of the Ancient World. Routledge, 1988. — Includes a detailed chapter on the Lighthouse of Pharos drawing on ancient textual sources and numismatic evidence.
• UNESCO World Heritage Centre. Underwater Cultural Heritage in Alexandria. UNESCO, 2010. — Policy document and feasibility overview for the proposed underwater museum, available via the UNESCO Digital Library.

Hero image: Bibliotheca Alexandrina at night, Alexandria, Egypt. © Wikimedia Commons / CC-BY-SA. Fort Qaitbay image © Wikimedia Commons / CC-BY-SA. Sphinx image © Wikimedia Commons / CC-BY-SA.