Wuliu Island, located in the southern area of Busan, is a Rock Island with different tide rising and falling conditions. Five or six islands are exposed every day. Wuliu Island, a protected natural area in Busan, consists of two parts: Yushuo Island (32m), Yingshuo Island (33m), Cone Island (37m) and Oyster Island (68m), which are uninhabited islands. The bottom of Yumou Island is an island, but the upper part is divided into two landings. When the tide fades, the sea water appears as an island. When the tide rises, the bottom of Yumou Island submerged by the sea water becomes two islands, thus including the surrounding islands, sometimes five islands and sometimes six islands. One of the two Yumou islands is called "Pine Island" because of its many pine trees, and the other islands is called "Shield Island" as if shielded against Pine Island. Six islands formed 100 million years ago in the Cretaceous Period in the sea breeze and wave erosion and uplift movement gradually changed to the present situation. In 1972, Wuliu Island was designated as the No. 22 monument of Busan. In 2007, it was awarded as the national designated cultural heritage. The sky trail on the rock cliff of 37 meters high was U-shaped. When the weather was not ideal, the rock with strong sea breeze was closed and steep view was far away. Fang Baiyun, the blue sky, fishing sails and the islands scattered in the sea are moving like mountains and loyal guards guarding the sea area.