Hepingdao used to be called Sheliao Island. The island has one gun emplacement on the west side and one on the east. It was built in 1626, modified by Liou Ming-chuan in 1886, and then by the Japanese. The western gun emplacement is located at the central high point of the island and is still a restricted military area. The eastern gun emplacement is located in a valley in the east of the island, facing Keelung Islet. From the emplacement, you are able to see Bitou Cape to the east and Yeliao Cape to the west. The structure of the gun emplacement is similar to Dawulun Fort. From the gun emplacement, you can see a strange sight. In the far distance, you can see dark and light colored seas mixing. This is the ‘Hailan Line’, created by the currents caused by undersea hills and troughs flowing in different directions.