I visited this WHS in April 2017. Located on Mt. Namhansan mountain, this fortress seems to be the preferred inscribed fortress among locals mostly because of the nature trails and hikes in the provincial park. I spotted a couple of interesting birds plus several common and black squirrels along the way.

In Spring, the fortress wall and pavilions are hidden well in the thick acacias. The loop hike is a medium difficulty 7.5km hike but is less photogenic and striking overall than Hwaseong and has less impressive defensive structures. Apart from the gates, the Emergency Palace is worth visiting.

My personal highlight was visiting the serene Buddhist temples of Mangwolsa and Janggyeongsa built by Buddhist monk-soldiers. These are situated 500-800 metres from the East Gate on a very steep hill. Both temples were fully decorated with colourful lanterns for Buddha's birthday when I visited. The UNESCO inscription plaque is just next to the tourist information booth near the Emergency Palace (closed on Mondays) and there is another stone marker near the East Gate.

To get to Namhansanseong it takes around 90 minutes. First you have to get to Sanseong Station by subway (exit 2) and then catch bus number 9 (all buses accept T Money Cards but you can also pay the driver directly). The afternoon return buses are very frequent so wait for one with enough free seats to go down the several hairpins!

Overall I enjoyed my visit but I'd rank it only slightly better than the Ganghwa Dolmens.