Datangmarsh, located near Hell Valley, was originally the outlet left by volcanic eruption. The hot spring water here is high temperature, more than 100 degrees. It is used by all other hot spring hotels. It can be said that this is the source of Dengbie hot spring. You can feel this natural hot spring at close range. There are free foot-soaking pools for tourists to experience. If you want to enjoy the other hot springs, or go back to the hotel, many hotels can feel the pure Japanese soup.