The Thunder God Cave is located on the rock face of the Double-Character Peak on Wudang Mountain. The shape of the Double-character Peak is like a huge turtle, and the color of the rock is like flames and thunder patterns. There is often a "boom boom" sound inside the cave, hence its name. The full name of the Thunder God Cave is "Nan Yan Yan Huo Lei Jun Cang Shui Sheng Cave". According to historical records, the Thunder God Cave was excavated during the Yuantong period of the Yuan Dynasty. It was the place where Zhang Shouqing, a famous Taoist priest on Wudang Mountain, practiced the Qingzheng Lei Technique and prayed for rain. It is said that Zhang Shouqing's prayer for rain was very effective. A Yuan Dynasty inscription preserved on Wudang Mountain once recorded as follows: In the first year of the reign of Emperor Huangqing, it did not rain in the capital. Instead, it was crowded with people. The Taoist priest Zhang Shouqing of Wudang was summoned to pray for rain, and it rained... After that, Zhang Shouqing, as per the royal family's request, prayed for rain several times, all of which were very effective. As a result, he was bestowed by the royal family the title of "Immortal of the Mystic Body and the Supreme Harmony".