Underwater archaeology
Underwater archaeology is a specialized field dedicated to uncovering the history of human cultures through artifacts and remains submerged in aquatic environments. With approximately 71% of the Earth's surface covered by water, many archaeological treasures, including shipwrecks, ports, and historically significant structures, remain unexplored. Historically, the study of underwater sites faced significant challenges due to limited technology; early efforts were often conducted by divers without adequate equipment, resulting in a lack of systematic exploration. The field began to develop in earnest in the latter half of the 20th century with advancements such as scuba gear, which revolutionized underwater explorations and allowed for more detailed archaeological investigations.
Underwater sites are often better preserved than land sites, as the absence of wind and environmental degradation protects them from disturbances. Notable milestones in the field include the discovery of Emperor Caligula's ships in Nemi Lake and the work of pioneering archaeologists who employed modern techniques to examine significant wrecks like the Grand Congloué and the Cape Gelidonya shipwreck. These efforts have allowed archaeologists to reconstruct historical narratives and gain insights into ancient trade and cultural interactions. Overall, underwater archaeology holds immense potential for expanding our understanding of maritime history and human activity near water.
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Underwater archaeology
Underwater archaeology is the science of learning about people and cultures of the past through remains that are submerged in bodies of water. Though large amounts of the world’s archaeological treasures are underwater, attempts to find and study them have long been hampered by a lack of technology. Only in the 1800s did diving mechanisms first allow people to study the sea floor for extended periods. However, technology and scientific methods did not intersect to create true underwater archaeology until the last half of the twentieth century.
Background
Fascination with the past has always been a part of the human experience. However, prior to the 1700s, archaeology was not considered a true science. Most artifacts were found accidentally or by profit-minded treasure hunters. In the 1700s, two ancient Roman cities, Pompeii and Herculaneum, were discovered almost perfectly preserved under volcanic ash. The scale of these sites greatly exceeded the capabilities of treasure hunters, and scientists took over the ensuing research. The work done at these sites and elsewhere during the 1700s and 1800s permanently established the science of archaeology. Archaeology became a methodical study of land, artifacts, structures, and remains with the goal of discovering truths about past peoples.
Even as discoveries on land opened up troves of new insights into ancient cultures, many fascinating discoveries remained relatively untouchable. These were underwater sites. Water covers approximately 71 percent of the planet’s surface. Humans have always lived near water. For many thousands of years, they have sailed the lakes, rivers, and oceans of the world. Waterways became early highways and centers for trade and travel. Millions of artifacts, large and small, and long-lost structures such as shoreline buildings, ports, harbors, and shipwrecks had been lost in the world’s waters.
Despite the extraordinary potential for underwater archaeology, the field was hampered by the lack of technology. Modern diving machines did not exist, and the earliest attempts to explore sunken harbors or shipwrecks were made by divers simply holding their breath. Though some of these divers were often trained to dive for marine creatures and could hold their breath for up to five minutes, their time and efficiency were severely limited. Additionally, they had no advanced lighting systems, navigational tools, or other devices to help them search the murky depths in a methodical way. Consequently, the field of underwater archaeology did not fully develop until relatively modern times.
Overview
A vast percentage of the world’s most valuable archaeological sites are underwater. These include, most famously, untold thousands of shipwrecks dating from ancient through modern times. Underwater sites also include remains of ports, harbors, fortresses, and other structures commonly built near waterways, as well as sites that were originally on land that has since flooded. Sometimes, single artifacts may be found underwater as well, likely either dropped from ships or swept away from shores long ago.
Underwater sites hold potential in many ways even greater than that of land-based sites. Underwater sites are often better preserved than land sites due to the lack of wind and other factors that can degrade physical materials. Additionally, the difficulty of access helps keep them safe from treasure hunters, development, and other disturbances common to land sites. Undisturbed shipwrecks, for example, can provide almost perfect “time capsule” conditions that capture exact moments from history in great detail.
Major interest in the potential of underwater archaeology likely first appeared in the 1400s, when Italian villagers discovered ancient wooden ships sunk in Lake Nemi. These turned out to be pleasure boats of the emperor Caligula, and the treasures and historical importance they held were significant. However, people had no way to access them aside from extremely short dives with no specialized equipment.
In the early 1800s, a breakthrough in diving technology arrived in the form of the diving helmet. The diving helmet was a spherical copper covering for the head with a glass window plate in the front. The helmet was fed pressurized air pumped through tubes from the surface, allowing divers to breathe underwater for extended periods. Helmet diving allowed for the first major underwater explorations of shipwrecks and other archaeological sites. For example, sponge divers with diving helmets discovered a Roman shipwreck off Tunisia. Later, similarly equipped Greek sponge divers found a shipwreck with cargo that included the Antikythera mechanism, an ancient computer designed to monitor astronomical phenomena.
Helmet divers explored many underwater sites and found many priceless artifacts. However, their explorations were mostly commercial, with valuable artifacts taken and sold without proper study or documentation. The first attempt at a truly archaeological study of a shipwreck most likely occurred in the late 1920s. Benito Mussolini, dictator of Italy, ordered the draining of Lake Nemi in order to expose the sunken ships. The ships were then housed in a warehouse for study and display before their destruction in World War II (1939–1945).
In the mid-1930s, helmet divers and history researchers visited the shipwreck of the Swedish ship Elefanten, another early milestone in underwater archaeology. However, the true breakthrough of the science came after World War II with the invention of scuba (self-contained underwater breathing apparatus) by Jacques-Yves Cousteau and Émile Gagnan. The inventors originally intended scuba for military purposes, but it became an invaluable key to underwater science, allowing divers to search the sea depths for much longer periods.
Cousteau himself demonstrated the value of scuba gear in the 1950s, helping archaeologist Fernand Benoît access the French shipwrecks known as the Grand Congloué. Careful scientific examination of these wrecks uncovered many historical treasures, including amphorae of wine that were sealed and somewhat drinkable. Following the Grand Congloué breakthrough, a wave of professional underwater archaeologists appeared. Among these was Peter Throckmorton, an American photojournalist living in Türkiye, who cooperated with local sponge divers to explore a Bronze Age-era shipwreck near Cape Gelidonya.
Inspired by Throckmorton’s pioneering work, a graduate student named George Bass and a diver and artist named Honor Frost joined his venture. Together with their team, they carefully mapped the Gelidonya shipwreck and recovered remarkable artifacts. The origins of the artifacts suggested the ship was a trading vessel, picking up and dropping off goods at ports throughout the Greek and Persian worlds. Using sound scientific principles and documentation, the team reconstructed the story of the ship down to five olive pits likely spat by one of the sailors some three thousand years ago. Their work with new techniques and technologies set a standard for modern underwater archaeological studies. Into the twenty-first century, advancements in technology, such as remotely operated vehicles, sonar mapping, and Artificial Intelligence-driven data analysis, have revolutionized underwater archaeology. However, tragedies, such as that of the Titan submersible, which imploded while traveling to the wreck of the Titanic, highlight the continued need for safety protocols.
Bibliography
Åkesson, Per. “History of Underwater Archaeology.” Nordic Underwater Archaeology, Nov. 2004, www.abc.se/~pa/uwa/history.htm. Accessed 8 Feb. 2025.
Bass, George Fletcher. Beneath the Seven Seas: Adventures with the Institute of Nautical Archaeology. Thames & Hudson, 2005.
Hale, John R. Classical Archaeology of Ancient Greece and Rome. The Great Courses/The Teaching Company, 2006.
Sanderson, Katharine. "Lost Titanic Sub: An Ocean Scientist Talks about Dive Safety." Nature, 2023, doi.org/10.1038/d41586-023-02074-x. Accessed 8 Feb. 2025.
“Threats to the Underwater Cultural Heritage.” UNESCO, 20 Nov. 2024, www.unesco.org/en/underwater-heritage/threats. Accessed 8 Feb. 2025.
Throckmorton, Peter. The Sea Remembers: Shipwrecks and Archaeology: From Homer’s Greece to the Rediscovery of the Titanic. Chancellor Press, 1996.
“What is Archaeology Underwater.” Advisory Council on Underwater Archaeology, acuaonline.org/what-is-underwater-archaeology. Accessed 8 Feb. 2025.