Seoul's Secret Places

Until the year 2000, Seonyudo was a working water purification plant supplying tap water to Seoul. Rather than demolish it, the city transformed the site into Korea's first environmentally reclaimed ecological park, deliberately preserving as much of the original industrial structure as possible.

Walking through, you'll find aquatic plant gardens and ecological forests growing directly out of and around the old purification facilities, along with the Hangang River Gallery and the Seonyujeong Pavilion — a genuinely unusual blend of industrial memory and intentional rewilding.

Surrounded on all sides by the flowing Han River, the park could easily draw heavy crowds given its location, but it remains a comparatively peaceful spot, especially outside weekend afternoons.

Noeul Park is one of five themed sections making up World Cup Park, an enormous ecological restoration project that converted the Nanjido waste landfill into green space ahead of the 2002 World Cup and new millennium.

True to its name — noeul means 'sky at sunset' in Korean — the park has become one of Seoul's most loved spots to watch the sun go down, its wide grassy fields filling with families, photographers, and campers rather than the more romantic, couples-focused crowd found at its sister park, Haneul.

Sculptures dot the open fields, and children run freely across grass that sits, almost unbelievably, on top of what used to be one of Asia's largest landfills.

One of four guardian mountains of the old Joseon capital, Naksan stands just over 100 meters tall — modest by mountain standards, but enough to offer a genuinely sweeping panorama over downtown Seoul, especially at sunset.

The park's main draw is its roughly 2km walking trail along the Seoul Seonggwak (Seoul Fortress Wall), running between the Hyehwamun and Heunginjimun gates — a route that was a favorite of the yangban ruling class during the Joseon Dynasty for exactly the same sunset views visitors still come for today.

A small exhibition hall, a hexagonal pavilion, and the Biudang pavilion (built to commemorate a Joseon-era official known for his integrity) add some structure to what's otherwise a simple, scenic walk.