Seongcheon Makguksu

Gyeongdong Market

It closes at 18:00 and most stores are shut on Sundays, so it suits a morning visit rather than an evening one. People come here for ginseng, medicinal herbs and ingredients more than for food.

Seoul Forest

The park is open 24 hours and never closes, but almost everything worth timing inside it does — the ecological forest, both conservatories and the floor fountain all keep separate hours, and the two indoor ones shut on Mondays. Tents, sun shelters and awnings are banned outright, which is the rule most picnic plans get wrong.

Uireung Royal Tomb

The former KCIA auditorium still stands inside the tomb walls. The July 4th North-South Joint Statement was announced in that building, so a Joseon royal tomb and twentieth-century political history share one precinct.

Dongdaemun Design Plaza

It closes three days a year and otherwise runs 10:00 to 20:00, but that figure covers the site, not what is inside it — each hall keeps its own hours according to whatever exhibition is running. Check the programme, not the building.