A 600-year industrial complex
In the Fanshan area of Wenzhou, a vast network of tunnels and chambers cuts deep into the mountains. This is not a natural cave system but created by more than 600 years of continuous mining that began in the Ming Dynasty (1368-1644). The objective was to extract alunite, a stone with the chemical compound alum. At its operational peak, the area, known as the "World's Alum Capital," contained 76 distinct mining sites and over 200 mining teams. The total alunite deposits here are estimated to exceed 240 million tons, which accounted for 60 percent of the world's known reserves.
The scale of the underground workings is immense. Generations of miners excavated countless tunnels, creating a subterranean world complete with ventilation shafts and large caverns that supported the industrial activity. This long history of extraction, which only ceased traditional operations in December 2017, shaped the geology and the culture of the region. The site is a national industrial heritage location, with sections like the Jilong Mountain caves being developed into an underground museum.