Consisting of a cinder cone in the middle of the crater and its tuff ring, Songaksan Mountain’s peak, which can also be considered as its mouth, has a depth of 69m and has completely preserved its active form. While it was previously unknown to visitors outside of those with archaeological reasons, recently it has become part of a well-known tour course and now many narrow paths lead to it.
Songaksan Mountain was used as Japan’s forward operating base during its invasion of China, the last line of defense during the final hours of WWII. Ruins of airfields, hangars, anti-aircraft artillery, and Canon Position constructed to target Doyang (渡洋) of China are scattered throughout, with 15 costal trenches below the coastal cliff, 4–5 of which have naturally decomposed and pose falling hazards. It has high preservation value because the cave was built using the shore cliff, and the trenches are located by the seaside to create excellent oceanic view.
With brother islands Gapado Island and Marado Island off in the distance, the ruins of the sea are sure to be a pleasing sight. The Origin and Etymology of the volcanic cone: To the northeastern face are seaside cliffs made of lava and stratum, and named Jeolul after the echo of crashing waves. The name Songaksan (松岳山) comes simply from the fact that this volcanic cone has many pine trees (Haesong in Korean), and the redundancy of the words “ak” and “san” (both means mountain) is a use of double-expression.