Produced by: Mohsin Shaikh
China’s sinkholes, or "tiankeng," hide untouched ancient forests deep within, where towering trees and rare plants have thrived for millennia.
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Scientists believe some tiankeng contain unknown animal species, making them one of the last unexplored biological frontiers on Earth.
Despite limited sunlight, plants in these sinkholes flourish thanks to rich reserves of nitrogen, phosphorus, and potassium, creating lush green sanctuaries.
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Tiankeng forests are home to prehistoric plant species, some dating back to the age of dinosaurs, surviving in isolation from the outside world.
With high humidity, stable temperatures, and underground water sources, tiankengs create a self-sustaining ecosystem unlike any other on the planet.
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Formed by collapsing limestone caves, these sinkholes are part of China’s UNESCO-listed karst landscape, a geological marvel shaped over millions of years.
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The air inside tiankengs is rich in negative oxygen ions, making these pits not just scenic but also potential natural detox zones.
As human activity threatens forests worldwide, these hidden ecosystems serve as a last refuge for rare and endangered plant species.
With only 300 tiankengs discovered globally—two-thirds in China—scientists believe many more could be hiding secrets deep beneath the earth.