Over 100 historic shipwrecks have been uncovered at a strategic maritime gateway - and researchers warn they may be at risk of fading away.
The vessels were found on the seafloor of the Bay of Gibraltar, part of the narrow waterway linking the Atlantic Ocean and the Mediterranean Sea, by researchers with Project Herakles.
The project, a joint venture between Spain's University of Cádiz and the University of Granada, has been underway for six years.
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Researchers have identified 150 underwater archaeological sites - the majority of which are shipwrecks, according to The Guardian.
The wrecks span centuries, from as early as the 5th century B.C. to World War II-era vessels.
The vessels include 23 Roman ships, four medieval ships, and the engine and propeller of a plane from the 1930s, according to The Guardian.
The findings were "not a chance discovery," said Felipe Cerezo Andreo, a lecturer in archaeology at the University of Cádiz - and the discovery took years in the making.
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The archaeologist told Fox News Digital in translated comments that his team's research has dramatically expanded what was previously known about the area.
"Before starting Project Herakles in 2019, only four underwater sites were known in the area; today we have information on more than 150 documented sites in just three years of work," he said.
"They can now be studied, protected and shared."
Researchers combined historical research with advanced technology to locate, map and study the wrecks.
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"We began by analyzing historical archives, museums and interviewing the local community of fishermen and divers, who know the seabed better than anyone," Andreo recalled.
Archaeologists then used advanced marine scanning technology to map the seafloor and locate buried shipwrecks, including magnetometers to "detect metallic anomalies."
Andreo said most of the recorded shipwrecks are from the 18th to 20th centuries - but older Phoenician, Punic and Roman vessels are also buried in the sands.
"The bay was a very important space in antiquity," he said. "We have evidence of settlements such as Carteia and Iulia Traducta that used these waters as their main port."
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He added, "Although the more recent ships are more visible, beneath them lie Phoenician, Punic, and Roman wrecks that tell the maritime history of both the Mediterranean and the Atlantic."
The scale of the findings suggests the area holds a continuous record of maritime history, he said.
"This tells us we are not dealing with isolated shipwrecks, but rather a submerged historical archive that has recorded every commercial and military movement since antiquity," said Andreo.
"The bay has functioned as a funnel of global history, and this is reflected in a seabed that preserves archaeological evidence."
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Most of the ships are in "critical" condition, he said - with the biggest threats coming from human activity, including port work, construction and looting.
"We have identified that a large portion of these 150 sites are at significant risk of deterioration," he said.
"Some are directly exposed on the seabed, making them vulnerable to erosion."
An invasive algae called Rugulopteryx okamurae is "drastically altering the marine environment and hindering the preservation and study of the remains," he said.
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"That is why, in Herakles, we prioritize non-intrusive documentation, [such as] photogrammetry and 3D models, to record everything before it disappears, following UNESCO principles of in situ conservation," he said.
The archaeologist stressed that the shipwrecks are still a living cultural resource, and that his team is "working to make this heritage accessible to everyone."
The team is planning an underwater park and VR experiences, so that people can explore the shipwrecks without risking further damage to the sites, Andreo added.
"We want society to feel that these shipwrecks are their 'museums beneath the sea,'" he said.
"Ultimately, protecting these remains is about protecting the pages of the book that explain who we are today."
