KUNMING, July 22 (Xinhua) -- Beneath the clear waters of Fuxian Lake in southwest China's Yunnan Province, nestled amid beautiful surrounding hills, lies a 518-million-year-old record of early animal life, so vital a discovery that it has quietly transformed the place into a guardian of ancient history.

The vivid blues catch the eye first. From the heights of Chengjiang, Fuxian Lake -- plunging over 150 meters at its deepest -- stretches out like a sapphire cradled by hills. Ming Dynasty (1368-1644) explorer and travel writer Xu Xiake once marveled at its legendary clarity, yet the lake's true wonder lies beyond its submerged mysteries. It is a living pact between a community and deep time, etched into the hills that surround it.

The name "Chengjiang," meaning "clear river," is no coincidence. This small county-level city in Yunnan nestles within a landscape defined as "70 percent mountains, 20 percent water and 10 percent flat land." Its global legacy rests on Maotianshan Mountain, an unassuming hill resembling a straw hat.

On July 1, 1984, paleontologist Hou Xianguang split open a slab of yellow shale and revealed a pristine Naraoia fossil. Since then, the Chengjiang Fossil Site has, for over four decades, yielded early Cambrian treasures, fossils from more than 20 phyla and over 300 species, 80 percent of them previously unknown to science. Nearly all existing animal phyla on Earth can trace their ancestral roots to this remarkable "cradle of life."

In 2012, it became China's first fossil-related World Heritage site, hailed as one of the world's most important fossil assemblages and the most remarkable discoveries of the 20th century.

Walk along the shoreline of Xiaowan Village today, and the pact comes into view. White-walled, dark-tiled guesthouses step gently down toward the eastern edge of Fuxian Lake, with no high-rises to disrupt the view. This quiet restraint lets nature take centre stage. Traces of deep time reveal themselves in subtle ways, with Cambrian fossils embedded in pocket parks and street corner designs.

Even village homes built decades ago unknowingly hold fossils. Elders recall digging local soil to make bricks and using unusual stones to steady tables or weigh down pickle jars. Only years later did they realize these were remnants of ancient life dating back hundreds of millions of years.

"Height is controlled, views are left open," said Li Yong, director of Chengjiang's natural resources bureau. "The goal is to protect everyone's right to see the lake and the surrounding hills." His guiding principle -- ecological priority, compact efficiency -- requires grey bricks and white walls, aiming to minimize visual disruption and blend architecture into the landscape.

Restraint brings lasting rewards. Fuxian Lake boasts Class I water quality, the highest standard in China, while its shores are now lined with bike paths and dotted with kayaks. Maotianshan Mountain is thriving, with mining banned and forests steadily returning to its slopes.

On the northern shore of Fuxian Lake, the world natural heritage museum of the Chengjiang Fossil Site houses more than 50,000 specimens. Visitors peer closely at the delicate segments of Naraoia and the lunging form of Anomalocaris.

"We put a great deal of thought into the exhibition design, with a 4D cinema and VR/AR experience zones that bring ancient fossils to life," said Wang Han, the museum's executive vice curator. "Visitors feel as if they've traveled through time, witnessing the Cambrian explosion firsthand."