Since this nomination expanded, I thought I would write a review specifically for Bukhansanseong (about 12 km wall length). I visited Bukhansanseong (Mountain Fortress) in the Summer of 2008. I spent the whole day hiking in Bukhansan National Park and visited multiple gates (there are 13 gates total). I researched the route and I was keen to walk much of the fortress before making my way to the parks famous granite peaks. The terrain is more challenging than Namhansanseong Fortress (built earlier 1624-1626). Bukhansanseong was built rapidly (less than a year) and the design utilized the physical terrain.  

Background History: During the reign of King Sukjong of Joseon (19th Ruler of the Dynasty) the Manchu conquest of China was ongoing, but nearing completion. Therefore, Korea was in a precarious position. Sukjong's father and grandfather witnessed the devastating effects of the slow collapse of the Ming Dynasty as Korea's closest ally. The Manchu invasion of Korea in 1627 and 1636 spurred Korea to improve their military and modernize the capitals primary defenses. The so-called 'Capital Fortifications of Hanyang' is more of a product of Sukjong's time than the first ruler(s) of Joseon. In fact, Bukhansanseong was completed in 1711 and linked to Hanyangdoseong via the Tangchundaeseong Defense Wall. Sukjong navigated political factions at the time, one which advocated war against the Qing (indeed the Ming came to the defense of Korea during the Imjin War). In the end, Sukjong avoided war and sought a policy of strength through defense and diplomacy. The Capital Fortifications of Hanyang are the product of those choices.

Pictured: Jungseongmun Gate

Bukhansanseong was first mentioned as potentially seeking World Heritage status in 2014. Including Bukhansanseong with Seoul's City Wall makes sense. Firstly, Hanyangdoseong and Bukhansanseong are linked both for the function as the primary defensive system of the capital and because of the improvements made to the Capital's fortifications during the reign of King Sukjong. While Seoul City Wall dates back to 1396, much of what we see today is result of the major restoration efforts ordered by Sukjong. This major restoration strengthened the cities defenses greatly (including rebuilding entire sections) and adding the mountain fortress as a connected series of defenses to protect the capital. 

I remember the rugged terrain of this trek well and it was an enjoyable hike. Namhansanseong is more intact (probably easier to repair) and because of its use to resist the Manchu Invasion, Namhansanseong has a more lasting impact on the History of the nation. Bukhansanseong stands out for using the granite bedrock and natural topography for several sections of the fortress wall. The landscape offers some stunning views and is also known for its greenery and Fall colors. 

Public transport is available to Bukhansan National Park. Because of its proximity to Seoul, Bukhansan National Park can be very busy on weekends, moreover it would be best to start your hike early.