Explore This! Welcome to Namhansanseong, a historic mountain fortress located outside of Seoul, South Korea. This 17th century palace was built as an emergency capital for the Buddhist monk-soldiers during the Joseon Dynasty. Explore this reconstruction of the king’s temporary palace, or Naehaengjeon, where he took refuge during the war against the Manchus. The various building techniques seen at Namhansanseong highlight the history of Korea’s urban fortification and marks the turning point in fortress design. Namhansanseong was declared a UNESCO World Heritage Site in 2014.