Human-built 5600-year-old submerged bridge found inside cave stuns scientists

A geology professor from the University of South Florida discovered a 5600-year-old stone bridge in an ancient cave that proves humans were present on the island of Mallorca much earlier than previously believed.

This discovery will change everything we thought and knew about early human history in the Western Mediterranean.

The question confounded archaeologists for decades. Logically, being so close to the mainland, the first signs of human settlement offshore should be on Mallorca. Instead, smaller islands farther out to sea suggest that humans skipped this island.

The recent discovery of an ancient bridge off the coast of Mallorca provides the first piece of conclusive evidence in this puzzle from human history that locates our early ancestors further back in time on the island of Mallorca and reveals how sophisticated they were.

Going underwater to find the first humans on Mallorca

In 2000, the team behind the study recently published in Communications Earth & Environment dived through passages in the ancient Genovesa Cave. As sea levels rose over the past 6000 years, the cave, mostly underwater, boasts stunning and distinct decorations such as calcite sculptures, according to Sci News. Besides the majesty of nature and time intertwined, however, they discovered a 25-foot-long bridge.

“The presence of this submerged bridge and other artifacts indicates a sophisticated level of activity, implying that early settlers recognized the cave’s water resources and strategically built infrastructure to navigate it,” Bogdan Onac told the University of South Florida in an official news brief, a geology professor and lead author of the newly published study.

How geologists reached back 6,000 years in the past

According to the study, a stone path and wall descend to a bridge that once crossed an underwater lake. Built without mortar or cement, the study authors continue, they stacked large limestone breakdown blocks and laid flat large boulders on top, up to 1.63m or 5.34 feet long. It was an access path to the only other dry chamber that provided researchers with the means to date the bridge.

Pottery from the Naviform period (3550-3000 years ago) led them to deduce that the bridge predated these tangible artifacts. Geological formations in the cave and a light-colored band on the bridge, which researchers explained to Vice would loosely compare to a bathtub ring, allowed them to calculate the bridge’s age to an even more consequential date, making this a significant discovery in human history.

“According to our chronology, the sea-level rise ceased and remained stable for several hundred years between 5,964 and 5,359 years ago,” Professor Onac said, which contributes to “a growing body of evidence of progressively earlier human settlements on many islands in the Mediterranean basin. According to the study, little progress has been made on the official timeline in recent years.

How early did humans arrive by boat to the islands?

The latest evidence shifted the chronology to about 4,400 years ago, but the bridge in Genovesa Cave has pushed back the signs of human life 2,000 years before that. Bones and pottery might extend the date 9,000 years into the past, but “inconsistencies and poor preservation of radiocarbon-dated material” challenged the viability of those findings; thus, they remain in theoretical territory. All the same, now, scientists can state that humans were active on the island about 6,000 years ago.

“The exact reasons behind the construction of these structures in Genovesa Cave remain elusive,” Professor Onac said to Sci News .

“Nevertheless, the chronological constraints posed by the depth of the bridge, coupled with the similar depth at which POS and the coloration mark occur, support the idea of an early human presence on the island by 5,600 years ago and potentially dating back as far as 6,000 years ago.”

“This research underscores the importance of interdisciplinary collaboration in uncovering historical truths and advancing our understanding of human history,” Onac concluded in The University of Florida’s news release . The underwater discovery opens up a structure in their world that elucidates these ancient people to possess impressive organization, manpower, and creativity .

As Vice notes, the bridge even proves that climate change is real.