Dongdaemun Design Plaza

Where it sits. The Dongdaemun Design Plaza occupies a large block on Eulji-ro in Jung District, at the edge of the Dongdaemun clothing wholesale quarter and a few hundred metres west of Heunginjimun, the great eastern gate of the old city wall. Three subway lines — 2, 4 and 5 — meet beneath it at Dongdaemun History and Culture Park station, and two of the exits open directly into the building. The site is hemmed in by the fashion malls that trade through the night, so the plaza's smooth silver mass sits in the middle of a district that is at its loudest between ten in the evening and five in the morning.

The building. Designed by Zaha Hadid with the Korean firm Samoo after a 2007 competition, built from 2009 and opened on 21 March 2014, it is a single continuous free-form volume of roughly 86,000 square metres over four floors above ground and three below. The skin is made of more than 45,000 aluminium panels, and because the surface curves in two directions almost everywhere, nearly every panel is a different shape — they were formed using techniques adapted from Korean shipbuilding, which is the detail that explains why the building could be made here and possibly nowhere else at the time. There are almost no right angles and very few visible windows. Circulation is by long ramps rather than stairs wherever possible, and the roof is a walkable landscaped park that folds down to street level, so the whole thing can be crossed on foot without entering a door.

What stood here before. The block was Dongdaemun Stadium, built in 1925 under Japanese rule and for decades the country's main sports ground, demolished in 2007 and 2008 to clear the site. Excavation then turned up a great deal more: a substantial run of the sixteenth-century Seoul City Wall, the two-arched Igansumun floodgate where the Cheonggyecheon passed out through the fortifications, and the foundations of a Joseon military training camp. These were conserved in place and are now the open-air Dongdaemun History and Culture Park on the eastern side of the site, with a small museum of the excavated material and a memorial to the stadium. The clearance also displaced the flea-market traders who had worked in and around the stadium, most of whom were rehoused in a purpose-built market at Sinseol-dong in 2008 — a transfer that many of them contested at the time, and one reason the informal secondhand trade around Dongmyo, ten minutes away, is as large as it is.

The argument about it. The project cost around 484 billion won and was pushed through against real opposition: over the loss of the stadium, over the cost, over the demolition of a public sports ground for a design showcase, and over an aesthetic that has no relationship whatsoever to its surroundings. It was central to Seoul being named World Design Capital in 2010, and it has since become one of the most recognisable buildings in Asia. Both readings are fair. Standing on the roof park at night, with the market towers blazing on one side and the excavated fortress wall lit below on the other, is the clearest available summary of how Seoul makes decisions about its own past.

On screen and in use. The interior — endless curving white corridors, indirect light, no orientation cues — is a favourite of Korean drama, film and music video whenever a scene needs to read as institutional, futuristic or unplaceable, and it appears in productions ranging from crime thrillers to idol videos. In its day job the building holds exhibition halls, a design museum, a design market of small studios and shops, an events plaza and the twice-yearly Seoul Fashion Week each March and October. A recurring winter installation covers part of the roof park with tens of thousands of illuminated artificial roses, which draws crowds well past midnight.

Getting there and timing. Dongdaemun History and Culture Park station, exits 1 and 2, or Dongdaemun station one stop north. The public routes, the roof park and the historic park are free and open around the clock; exhibitions are ticketed and keep daytime hours, generally closing one day a week. Evening is the better visit — the aluminium skin reads best under the lighting scheme, and the surrounding wholesale market only starts working properly after dark. The building is genuinely step-free, ramped throughout, with lifts and accessible toilets, which makes it one of the easiest major sites in Seoul to visit with a wheelchair or a pushchair. Combine it with Gwangjang Market fifteen minutes west along the Cheonggyecheon, or with the wall walk north over Naksan.