The Giant Funnel of the Earth: Xingwen Stone Sea Great Tiankeng and the Karst Underworld

The "Big Dipper" of the Karst World

1.Located in the core area of the Xingwen: Stone Sea Scenic Area in Xingwen County, Yibin City, Sichuan Province, the Great Tiankeng (also known as the Grand Whirlpool) is a geological marvel that defies imagination. Situated approximately 150 kilometers from Yibin city center, this site is a crown jewel of the UNESCO Global Geopark and a key component of the "South China Karst" World Natural Heritage. The Xingwen Great Tiankeng is celebrated as the "largest funnel-shaped sinkhole in the world." Unlike typical vertical sinkholes, this massive depression resembles a gigantic bowl carved into the earth, with a diameter of 650 meters and a depth of 666 meters. Its volume is so immense that the bottom area is equivalent to 60 football fields. Standing at the rim and looking down, visitors are met with a breathtaking abyss where cliffs drop vertically, ancient vines cling to the rocks, and a primitive forest thrives at the bottom, creating a mysterious "underworld" atmosphere that contrasts sharply with the sunny plateau above.

A Trinity of Geological Wonders

2.The Great: Tiankeng is not an isolated feature but the heart of a unique geological "Trinity" found in Xingwen: The Stone Sea, The Tiankeng, and The Caves. Formed about 200 million years ago during the Permian period, this landscape is a living textbook of earth's history. The sinkhole was created by the collapse of a massive underground cavern hall. Today, it serves as a window into the subterranean world. The pit walls are steep and knife-like, displaying jagged strata that tell the story of the ocean's retreat and the mountain's rise. At the bottom, the sinkhole connects to a complex system of underground rivers and caves, including the famous Tianquan Cave (Sky Hole Cave), which spans several kilometers. This interconnection allows visitors to experience a journey from the "Sea of Stones" on the surface, down into the "Funnel of the Earth," and finally through the "Palace of the Underground," offering a complete exploration of the karst system.

The Miracle of Light and Water

3.One of the most mesmerizing features of the: Great Tiankeng is the "Red Army Lake" (or simply the underground lake) and the seasonal waterfalls that cascade down the crater walls. During the rainy season, water gathers from the surrounding mountains and plunges hundreds of meters into the pit, creating a thunderous roar. When sunlight strikes the mist generated by these waterfalls, brilliant rainbows frequently appear, arching across the dark abyss. This phenomenon, known as the "Rainbow Waterfall," transforms the terrifying depth into a scene of enchanting beauty. The microclimate inside the Tiankeng is distinct; it is cool in summer and misty in winter, rich in negative oxygen ions, making it a "natural oxygen bar." Visitors can descend via a winding plank road that clings to the cliffside, or take a sightseeing elevator to reach the bottom, passing through layers of geological time and lush vegetation that includes rare ferns and ancient trees.

A Sanctuary of Miao Culture

Culturally, the Xingwen Stone Sea and its Great Tiankeng are deeply intertwined with the traditions of the local Miao people. For centuries, the Miao ethnic group has regarded the Tiankeng as the "Mouth of the Earth Mother." Legend has it that the sinkhole was formed when a celestial deity smashed the earth to reveal a sanctuary for the people. During the annual Miao Flower Mountain Festival or the Torch Festival, the area comes alive with cultural vibrancy. Local Miao people, dressed in colorful traditional attire, perform the energetic Bamboo Dance and sing folk songs near the crater rim. The "Sa" worship rituals (worshiping the rock and nature gods) are often conducted here, praying for favorable weather and harvest. The fusion of the majestic, silent geological void with the spirited, colorful Miao culture adds a profound humanistic dimension to the natural spectacle. Whether you are an adventure seeker exploring the dark caverns or a photographer capturing the "Sea of Stones" rolling like waves, the Xingwen Great Tiankeng offers a journey into the heart of the earth.