Yangsan Singiri Fortress

The Fortress in Singi-ri (Hanja), sometimes called Sŏnangsansŏng was a Korean fortress in what is now Yangsan, South Korea. On January 21, 1963, its former site was made a Historic Site of South Korea. It is not certain when the fortress was built. A fortress in this area is mentioned in the Samguk sagi as being constructed around this area in 687 (Korean calendar), but it is not certain if this is the fortress in question. Many relics of the Silla culture have been found in the area, so it is presumed to be made by Silla.

Fort data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).