Historic Monuments and Sites in Kaesong
UNESCO says three different sections of wall and a few gates in Kaesong have enough historical value to be part of the site.  The Palocham Wall was built in 896 c.e., just before the Koryo Dynasty.  The Outer Wall was built in 1009-1029 and connected the city to the nearby Songak, Puhung, Tokam, Jine and Ryongsu Mountains.  The wall was built to defend the city, but it also shows what people believed about the magic or spiritual power of mountains.  The Inner Wall was built in 1391-3, just as the Koryo Dynasty was ending.