Seoul Mongchontoseong Earthen Fortification (서울 몽촌토성)

Mongchontoseong Earthen Fortification is an ancient earthen fortress built during the Hanseong period of the ancient Korean kingdom of Baekje (BC 18-AD 660). It is believed to have been constructed in the 3rd to 4th centuries. Utilizing the natural advantages of the Hangang River, it served defensive purposes with its trench  and log barrier. Excavated relics from the Baekje era are on display at the Seoul Baekje Museum. The site is situated within the Olympic Park in Songpa, Seoul.