In the steep, narrow valley of the Longchuan River, the three-story Heijing Well Salt Historical Museum stands on a nine-hundred-square-meter footprint. It sits directly beside the ancient Dajing Salt Well, also known as the Black Cow Well. Local memory preserves the story of Li Azhao, a Yi woman who followed her unusually healthy black cow to this spot, where she watched it lick the salt-saturated earth. This discovery initiated over two thousand years of salt extraction, transforming this remote mountain cleft into a wealthy regional capital. During the Ming and Qing dynasties, the taxes collected from these wells funded over half of Yunnan Province's total salt revenue.

Inside the fourteen-hundred-square-meter building, six galleries—including the Preface Hall, Salt Capital History, and Wellside Dwellers—chronicle this industry. Visitors encounter the physical realities of ancient engineering. Outside, the Dajing Well descends as a fifty-meter-deep oblique shaft, its mouth framed by a stone archway three meters high. For centuries, laborers descended these slippery stone steps to haul brine. They used wooden and bamboo dragon pumps to draw the salty water to the surface, pouring it into large settling basins.

The museum displays the tools of this grueling labor. Visitors can see the heavy wooden buckets that back-carriers strapped to their shoulders, carrying wet brine up from the dark depths. The air in the galleries carries the memory of the wood-fired boiling pans where workers crystallized the brine into pure white, delicious salt blocks. Outside, horse caravans gathered, their copper bells ringing through the stone streets of Heijing as they carried the precious mineral along the Southwest Silk Road.

Opened for free on May 1, 2023, this institution preserves forty-six historic wells. It offers a quiet space to contemplate the physical grit of the workers, the administrative precision of the imperial salt officials, and the enduring legacy of a town built entirely on a subterranean sea of brine.