Thousands of Years Later, the Great Wall of China Is Still Revealing Secrets: It Turns Out It’s Older Than We Thought

China is a global leader in mega-construction, renowned for its towering skyscrapers and vast bridges—even the abandoned ones. This fascination with monumental engineering is nothing new. Among its most iconic structures, the Great Wall stands as a testament to this legacy. Spanning over 13,000 miles, the Great Wall was once believed to have revealed all its secrets, but new research has proven otherwise.

Beyond its age, scientists have also discovered an unexpected natural defense: a protective “bioshield.”

Rewriting history. Originally built to defend China’s northern border, the Great Wall was expanded by successive dynasties. Until now, experts believed construction began between 770 and 476 BC. However, recent excavations by the Shandong Institute of Cultural Relics and Archaeology suggest an even earlier start.

Between May and December 2024, researchers excavated 11,840 square feet in the village of Guangli. There, they unearthed a section of the Wall dating back to the Western Zhou dynasty, between 1046 and 771 BC—making it 300 years older than previously believed.

Advanced building techniques. This newly discovered section evolved through multiple construction phases. Initially, during the Zhou dynasty, builders used tamped earth. Later, they reinforced the structure with compacted earth and metal elements, significantly improving durability.

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While today’s Great Wall averages 16 feet in width, these early sections ranged from 32 to nearly 100 feet wide. The discovery also suggests the Wall wasn’t a single structure but part of a larger fortification, including trenches and ditches. To date the discovery, the team took samples of soil, animal bones, plant remains, and artifacts and carried out carbon-14 and optically stimulated luminescence tests.

The Great Wall isn’t a single structure but a series of sections built by various dynasties.

Changing our understanding of the past. Beyond its age, this discovery has far-reaching historical implications. Lead researcher Zhang Su calls it “a milestone in clarifying the origins and development of China's Great Wall research.”

Among the remains are sections from the Han dynasty, dating back 2,200 years.

Beneath this section, archaeologists found remains of two Zhou-era residences, likely part of a small settlement that guarded a crucial river trade route. Nearby, they also uncovered the lost city of Pinying, mentioned in historical texts but never before confirmed. The findings suggest the Wall wasn’t just a defensive structure but a strategic pillar in controlling key transportation routes.

There are also more recent Ming-era remains.

The Great Wall’s hidden “bioshield.” The revelation that the Wall is older than thought isn’t the only recent breakthrough. A 2023 study uncovered another secret: a protective biocrust—a layer of rootless plants and microorganisms covering parts of the structure.

Typically found in arid landscapes, this natural layer acts as a shield against air, water, and wind erosion. According to CNN, researchers typically don’t search for it in man-made structures. Unlike traditional plants, which can damage monuments with their roots, this biocrust strengthens the Wall, effectively gluing its materials together and slowing decay.

While vegetation can damage the structure, the yellowish patches found on it are lichens, part of the protective biocrust.

This discovery upends previous timelines. The Great Wall of Qin, a 400-mile stretch once believed to be the oldest, no longer holds that title. More remarkably, the findings reveal that construction on the Wall spanned over 1,000 years—longer than previously thought. The Wall’s expansion continued until the Ming dynasty halted its growth in the mid-1600s after annexing Mongolia, rendering it obsolete as a defensive structure.

Even after thousands of years, the Great Wall continues to surprise us—proving that history is never truly set in stone.

Images | Hanson Lu (Unsplash)

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