Hot spring industry is developed. Tuankou Hot Spring Town in Lin 'an is located in the southwest mountainous area of Lin 'an, Hangzhou. This is a basin surrounded by mountains. There are four rivers, namely, Turbulent Source, Tangxi, Shen Xi and Liangxi, which flow into Changhua River after meeting in the basin. The geographical location is superior and the hot spring industry is developed. There is a unique "mountain spring city" pattern here. Since ancient times, it has been a treasure trove of "eight mountains surrounded by four waters" and is known as "four waters falling into the hall".