Donggosanseong Fortress

Donggosanseong Fortress is a mountain fortress built during the Unified Silla period. Its name was given during the reign of King Sunjo of the Joseon Dynasty when the fortress across from it was called Namgosanseong. The fortress has a circumference of 1,712m, extending 314m east-west and 256m north-south, making it a relatively large-scale mountain fortress. The walls were constructed using the valley-encircling method. It has long been presumed to be the palace fortress of Wansanju, which was the capital of Later Baekje founded by King Gyeon Hwon. In a 1990 excavation, a building site measuring 22 kan in front and 3 kan on the sides, totaling 66 kan in area, was discovered. This is the largest single building site excavated in Korea, supporting the claim that this was the palace of King Gyeon Hwon.