Built and expanded as an emergency capital in the early seventeenth century, its walls run for kilometres along the ridges, with gates, command posts and temples inside, and it became a World Heritage site in 2014. The fortress is remembered for a bitter episode: in the winter of 1636 to 1637, King Injo fled here as the armies of the Qing invaded, and after a siege of more than forty days in the cold, he came down and submitted, kneeling before the Qing emperor. Koreans still regard it as a moment of national humiliation and resilience at the same time.
Today the area inside the walls is a peaceful place of pine forests, restored buildings and trails along the ramparts, with views over the whole of Seoul on clear days. At weekends the hills fill with walkers in bright outdoor clothing, and the restaurants near the centre of the fortress specialise in dishes such as chicken boiled with herbs and rice, eaten after a long hike.
The road up to the fortress from Seongnam winds up the slopes of the mountain in a series of bends and is popular with local riders and drivers on fine days, which also means traffic, cyclists and pedestrians at weekends. The other access roads, from the Gwangju side, are quieter. As everywhere in Korea, motorcycles are not allowed on expressways, so the approach from Seoul uses ordinary roads, which can be slow in rush hour. South and east of the city, beyond Gwangju, roads lead into the hills around Paldang Lake and the Han River, which are well worth exploring on a free afternoon.
Seongnam, with over a million inhabitants, is right next door and offers all services, and fuel is easy to find along the main roads. If you visit in autumn, the colours on the fortress walls are wonderful; in winter, the roads up the mountain can freeze, so check the conditions before you go. Bring water for the walk along the walls, as the climbs are steeper than they look.