The tallest of Seoul's four guardian peaks, Bukaksan (342m) was off limits to the public for 38 years following a dramatic assassination attempt by North Korean agents on then-President Park Chung-hee in 1968. Security remains tight along this spectacular 2.5km section of the Seoul City Wall that rises steeply from Changuimun, the old subgate in Buam-dong, hopping over the peak above Cheongwadae to the Malbawi Information Center near Sukjeongmun, the main north gate, which can also be accessed from Samcheong Park.
This section of the fortress wall is also open only during daylight hours and photography is permitted at designated spots only, such as Baekakmaru, the summit viewpoint. You're also required to show your passport at Changuimun in exchange for a pass, which must be worn at all times. The wall is in excellent condition, and with plenty of soldiers and CCTV cameras, there’s a vivid sense of its original purpose as the city’s last line of defence.
From the subway, take bus 1020, 7022 or 1711 to Changuimun.