Underwater Archaeology: Shipwrecks, Sunken Cities, and What Lies Below
Water is archaeology's paradox: it destroys most materials on contact and yet preserves others indefinitely. Anaerobic conditions on the seabed — low oxygen, stable cold temperatures, soft sediment — preserve organic material that would vanish within decades on land. The result is that shipwrecks and submerged sites sometimes offer the most complete assemblages in the entire archaeological record: hull timbers, rigging, cargo in its original packing, personal items, food stores, and the tools of the craft all survive together. The challenge is getting to them without destroying what the water preserved.
Uluburun Shipwreck, Turkey
In 1982 a sponge diver named Mehmed Cakir found what he described as "metal biscuits with ears" on the seabed off Cape Uluburun near Bodrum in southwestern Turkey — oxhide copper ingots from a Bronze Age wreck. George Bass and Cemal Pulak of the Institute of Nautical Archaeology excavated the wreck between 1984 and 1994, completing over 22,000 dives. The cargo, dated by radiocarbon and the accompanying Mycenaean pottery to around 1300 BCE, was the most diverse international assemblage from the Late Bronze Age ever found: ten tonnes of Cypriot copper oxhide ingots, one tonne of tin ingots (from a source probably in Afghanistan), Canaanite amphorae of terebinth resin, Egyptian gold jewellery, a gold scarab of Nefertiti, ebony logs from Africa, Baltic amber, ivory, glass ingots, and a folding wooden diptych (the earliest known writing board). The wreck documents the interconnected trading world of the eastern Mediterranean at its Late Bronze Age peak. The finds are in the Bodrum Museum of Underwater Archaeology.
Vasa, Stockholm, Sweden
The Swedish warship Vasa sank on her maiden voyage on 10 August 1628 in Stockholm harbour, taking approximately thirty sailors down with her. She lay in 32 metres of water in the cold, low-salinity brackish water of the Baltic, where the wood-boring mollusc Teredo navalis cannot survive. When Anders Franzen located her in 1956 and salvage began in 1961, the ship emerged almost intact: the hull, mast stumps, two of her original four gun decks, sails, rigging, personal belongings of the crew, and the skeletons of those who drowned were all preserved. The Vasa Museum, opened on Djurgarden island in 1990, was purpose-built around the ship: the vessel itself, 69 metres long, is the permanent exhibit. It is the best-preserved seventeenth-century warship anywhere and the most visited museum in Scandinavia.
Mary Rose, Portsmouth, England
The Tudor warship Mary Rose, which served Henry VIII and sank in the Solent in 1545 during an engagement with a French fleet, was located in 1971 by Alexander McKee and excavated by Margaret Rule and a team of volunteer divers throughout the 1970s. The hull was raised in 1982 in what remains one of the most technically complex salvage operations in maritime archaeology. The ship carried longbowmen — 138 longbows and over 3,000 arrows were recovered, along with bodkin arrowheads, leather bracers, and the skeletons of men who were apparently trapped below decks when she heeled and went under. The Mary Rose Museum in Portsmouth's Historic Dockyard displays the hull, now preserved after decades of polyethylene glycol treatment, alongside thousands of artefacts.
The Antikythera Mechanism
In 1900, sponge divers sheltering from a storm off the small island of Antikythera between Crete and the Peloponnese discovered an ancient shipwreck. Between 1900 and 1901, Greek navy divers recovered bronze and marble sculptures, pottery, and jewellery, and a lump of corroded bronze that was initially disregarded. When it dried and split, it revealed a complex gear mechanism. The Antikythera Mechanism — as it became known — is a first-century BCE Greek analogue computer for calculating astronomical positions and calendars: the positions of the sun and moon, lunar and solar eclipses, and the dates of the Panhellenic Games. It contains at least thirty meshing gears of extraordinary precision. Nothing remotely comparable in mechanical sophistication appears in the archaeological record again for over a thousand years. The mechanism and the other wreck finds are in the National Archaeological Museum in Athens. A second investigation of the wreck by an international team from 2017 onward has recovered additional human skeletal material.
Alexandria Magnus Portus and the Submerged Royal Quarter
The ancient harbours of Alexandria, Egypt — the Great Harbour and the Eunostos Harbour — have been the subject of underwater excavation since Franck Goddio and the Institut Europeen d'Archeologie Sous-Marine (IEASM) began systematic survey in 1996. The submerged remains of the Ptolemaic royal quarter include the palace foundations, quays, and statuary; the red granite sphinx of Ramesses II sits on the harbour floor. The nearby submerged city of Thonis-Heracleion, mapped by Goddio's team from 2000 onward, was a major port city at the mouth of the Canopic branch of the Nile, largely destroyed by earthquakes and liquefaction events. Hundreds of statues, bronze vessels, gold jewellery, and the hull of a ritual boat have been recovered. The finds are displayed in the Bibliotheca Alexandrina Antiquities Museum and in European touring exhibitions.
Caesarea Maritima Underwater Archaeological Park, Israel
The Herodian harbour of Caesarea Maritima, built between 22 and 10 BCE by Herod the Great using volcanic pozzolana concrete imported from Italy — the first large-scale use of hydraulic concrete in the ancient world — now lies largely submerged due to isostatic subsidence. The Caesarea Underwater Archaeological Park, managed by the Israel Antiquities Authority and the Samuel Rothberg School for Overseas Students at Hebrew University, permits recreational diving over the harbour structures: the massive breakwater rubble mounds, the lighthouse platform, and the warehouse foundations are all visible underwater. A marked snorkel trail supplements the diving. Diving permits are arranged through the local dive operators in Caesarea.
Methods: photogrammetry and excavation permits
Underwater excavation uses the same principles as terrestrial excavation — context recording, finds bags, stratigraphic sequence — but adapted for a three- dimensional, low-visibility working environment. Photogrammetry has transformed the work: a diver swimming a systematic pattern with a camera produces image sets that are processed into detailed three-dimensional models of the seabed, allowing measurements and planning from a computer model rather than from underwater drawings. Side-scan sonar and sub-bottom profilers locate wreck deposits before diving begins; remotely operated vehicles (ROVs) survey deep water sites inaccessible to divers.
Permits are required for all archaeological diving in virtually every jurisdiction. In Turkey, the Ministry of Culture issues permits; in UK waters, the Protection of Wrecks Act covers designated sites; in Israeli waters, the Israel Antiquities Authority controls access. Recreational divers visiting protected underwater sites — Uluburun's wreck site, the Caesarea park, the Antikythera area — must follow site rules, which universally prohibit touching or disturbing any material. The same rationale applies as on dry land: context is evidence, and disturbed context is destroyed evidence.
Visiting underwater archaeology
Several of the sites mentioned above are accessible to non-specialist visitors. The Bodrum Museum of Underwater Archaeology occupies Bodrum Castle and displays the Uluburun finds comprehensively. The Vasa Museum in Stockholm requires no diving qualification and is one of the finest museum experiences in Europe. The Mary Rose Museum is in Portsmouth's Historic Dockyard adjacent to HMS Victory. For those with dive qualifications, the Caesarea Underwater Park is the most accessible formal underwater archaeological experience in the Mediterranean. All associated land sites are on the map.