Introduction to the long underground river: The long underground river originates from the Jiulong and Baikeng areas. Its water source meanders from the underground limestone layer and stretches for dozens of miles. Its river course is currently 1,043 meters long, with a width of 12 meters and a narrowness of 15 meters. More than 800 meters of it are available for boating, making it the best in the country for navigation of Dongfu springs. As the boat sails on the river, the water turns with the cave and the scenery moves with the boat. It can be said that the boat is walking on the river and people are swimming in the painting.