Coordinates: 30°55′50″N 119°29′33″E / 30.93056°N 119.49250°E
Taiji Cave (simplified Chinese: 太极洞; traditional Chinese: 太極洞; pinyin: Tàijí Dòng; literally: "Cave of the Supreme Ultimate") is a karst cave located on Shilong Mountain (石龙山) in Guangde County, Xuancheng City, Anhui Province, People's Republic of China, where the provinces of Jiangsu, Zhejiang and Anhui meet. Ming Dynasty writer and poet Feng Menglong described the cave as one of the "Four Absolutes Under Heaven" (天下四绝 Tīanxià Sìjué). It is also considered a primary "Place of Enlightenment" (道教道场 Dàojiào Dàochǎng) by Taoists, similar to the Bodhimanda of Buddhism. The 200-million-year-old cave is divided into dry and wet layers representing the yin and yang of Chinese philosophy.
In February 2004, the Chinese State Council included the cave on its fifth list of National Scenic Attractions. It is also a 4A rated National Tourism Area.
At 5.4 kilometres (3.4 mi) in length and covering a surface area of 140,000 square metres (1,500,000 sq ft), Taiji Cave is the largest natural limestone cave in East China. The cave's first chamber extends to 1,600 square metres (17,000 sq ft) and has a height of 5 to 10 metres (16 to 33 ft). To date nineteen separate chambers have been opened to visitors. There are more than 160 features inside the cave, including the "Ten Large Landscapes" (十大景观 Shí Dà Jǐngguān).