We went up Namsan in the late afternoon and stayed until after dark, which is the best way to visit: relaxed green views over Seoul in daylight, then the love-lock fences and the tower lit up at night. Inside the tower there is more than the observatory, including the n.Grill revolving restaurant with afternoon tea, lunch and dinner courses, the Hancook Korean restaurant with a weekday lunch course, and a K-pop VR theatre. Take the Namsan cable car or the 01A/01B buses up, and go around sunset to see both views.