The tallest building in Seoul is Lotte World Tower, at 555.7 metres and 123 floors, opened to the public in April 2017. It stands in Jamsil, in the south-eastern district of Songpa, and it is the tallest building in South Korea and among the ten tallest in the world. It also took thirteen years to get permission, because it sat directly in the approach path of a military airbase and the eventual solution was to rotate a runway.
The Runway That Had to Move
Lotte first applied to build a supertall tower on the Jamsil site in the mid-1990s. The Ministry of National Defense objected repeatedly, because the site lay in the flight path of Seoul Air Base at Seongnam, a military airfield roughly six kilometres south-east.
The dispute ran through three presidencies. It was resolved in 2009, when the government approved the project on condition that the airbase's runway be rotated by three degrees at Lotte's expense — reported at around 100 billion won — to move the approach corridor away from the tower.
Construction permits followed in 2010 and ground was broken in 2011. The tower topped out in December 2015, was structurally complete in 2016, and opened to the public on 3 April 2017.
The Sinkholes
Public confidence in the project was badly damaged in 2014 and 2015, when a series of sinkholes appeared in the streets around the construction site and cracks were found in a nearby apartment block. Jamsil sits on alluvial deposits near the Han River, and residents blamed the tower's excavation and groundwater pumping.
Seoul's city government commissioned investigations, some of which attributed the sinkholes to nearby subway tunnelling rather than to the tower, and Lotte was required to carry out extensive monitoring. Separate incidents at the lower Lotte World Mall — a cracked aquarium tank, a falling ceiling panel, a vibration event in a cinema — forced temporary closures in 2014 and 2015.
The safety review process delayed the opening of parts of the complex by more than a year, and it is the main reason the tower's public reception in Korea was more sceptical than triumphant.
The Design
Kohn Pedersen Fox produced the final design after several earlier schemes were rejected. The tower tapers continuously from a square base to a rounded top, with a seam running up one face where the two curved surfaces meet, and the architects described the profile as drawing on Korean ceramics, calligraphy brushes and porcelain.
The structure combines a reinforced concrete core with eight steel megacolumns and three outrigger levels. Wind was the governing load rather than earthquakes, and the tapered form itself is the main wind-mitigation measure — it disrupts the vortex shedding that makes tall square buildings sway.
The foundation is a 6.5-metre-thick concrete mat sitting on 108 bored piles driven into bedrock. Pouring it took 32 continuous hours and around 5,300 truckloads of concrete, one of the largest continuous concrete pours ever carried out in Korea.
Seoul Sky
The observation deck, called Seoul Sky, occupies floors 117 to 123 and sits 478 metres above ground at its highest point. It includes a glass-floored section on the 118th floor and, at 541 metres, what was certified as the world's highest glass-bottomed observation deck when it opened.
Getting there takes about a minute. The double-decker Sky Shuttle elevators run at up to 10 metres per second, among the fastest in the world, and were supplied by Otis.
Below the observatory the tower holds offices, a Signiel hotel occupying floors 76 to 101, and officetel residences. The lower podium contains Lotte World Mall, an aquarium, a concert hall and a cinema.
The Chaebol Behind It
Lotte World Tower is a Lotte Group project, and the group's founder Shin Kyuk-ho pursued a landmark tower in Seoul for most of his career. Lotte began in Japan in 1948 and expanded into Korea from 1967, and the Jamsil complex — mall, department store, hotel, theme park and now tower — is its single largest asset.
The approval fight in 2009 became politically contentious after the project was cleared under the Lee Myung-bak administration, and the circumstances were revisited by prosecutors in later corruption investigations into Lotte and into the presidency of Park Geun-hye.
Chairman Shin Dong-bin was convicted of bribery in 2018 in connection with the wider scandal and served several months before his sentence was suspended on appeal. The tower opened in the middle of all of it, which is part of why the launch was muted.
The Numbers
The tower cost a reported 3.8 trillion won, roughly 3 billion dollars at the time. It has around 500,000 square metres of floor space, 61 elevators and a workforce of several thousand across the offices, hotel and observatory.
It was designed for a 1-in-100-year wind event and for seismic loads up to magnitude 9, a specification driven less by Korean seismicity — which is low by regional standards — than by the consequences of failure in a building holding tens of thousands of people.
Seoul Sky drew over a million visitors in its first hundred days and has since settled into the low millions annually, making it one of the most visited observation decks in Asia. On 31 December each year the facade carries a countdown display visible across the southern half of the city.
The Rest of the Seoul Skyline
Nothing else in Seoul comes close. The second tallest building in the city is the Parc1 Tower A in Yeouido at 333 metres, completed in 2020, followed by the Three IFC at 284 metres and the 63 Building at 249 metres.
The 63 Building, finished in 1985 on Yeouido island, was the tallest building outside North America when it opened and held the Korean record for two decades. Its gold-tinted glass made it the defining image of Seoul's skyline through the 1988 Olympics.
Seoul's tall buildings cluster in three areas: Yeouido, the financial island in the Han River; Gangnam and Jamsil south of the river; and a smaller group around Jongno and the traditional centre, where height is restricted to protect views of the palaces and Bukhansan.
Namsan Tower Is Not a Building
N Seoul Tower, on Namsan hill in the middle of the city, is often assumed to be Seoul's tallest structure. The tower itself is 236.7 metres, but it stands on a 243-metre hill, so its top is around 480 metres above sea level — higher than most of Lotte World Tower.
It is a communications and observation tower rather than a habitable building, so it does not enter building rankings, the same distinction that separates the CN Tower from Toronto's skyscrapers and Sydney Tower from Crown Sydney.
It opened to the public in 1980 and remains the more photographed of the two, because it is visible from almost anywhere in the old city and Lotte World Tower is not.
Korea's Height Restrictions
Seoul has long capped building heights in much of the historic centre. Regulations protect sightlines to Gyeongbokgung and the other palaces, to the city walls and to the mountains that ring the basin, and buildings within those zones are generally held well below 100 metres.
The city's 2030 plan set a general 35-storey ceiling on residential buildings across much of Seoul, introduced in 2014, which was relaxed in 2023 to allow taller apartment blocks in designated areas. Redevelopment pressure in Gangnam and Yeouido had made the cap politically difficult to hold.
Outside the protected zones, the constraints are aviation and geology rather than heritage. Gimpo Airport imposes limits across the west of the city, which is why Yeouido's towers stop where they do.
What Nearly Got Built Instead
Several taller Korean projects have been announced and abandoned. Busan Lotte Town Tower was designed at 510 metres and has been stalled for over a decade with only the podium built. The Seoul Light DMC Tower in Sangam was planned at 640 metres and cancelled in 2016 after failing to attract investors.
Hyundai's Global Business Center in Samseong-dong was approved at 569 metres, which would have made it Korea's tallest, and was then redesigned in 2023 into a cluster of shorter towers of around 250 metres following a review of costs and the same airbase constraints that delayed Lotte.
The pattern is consistent. Korea has produced one supertall building and a long list of cancelled ones, and the reasons are usually some combination of aviation clearance, financing and the difficulty of filling that much floor space.
Visiting
Lotte World Tower is directly above Jamsil station on Seoul Metro Lines 2 and 8. Seoul Sky tickets are timed, and the lift lobby is on the basement level of the mall rather than at street level.
The view runs north across the Han to the mountains, east towards Namhansanseong, and west across the whole city to Yeouido and Namsan. On clear days the Bukhansan ridgeline is visible about 25 kilometres away, and the observatory publishes daily visibility forecasts.
The tower is floodlit at night and its facade doubles as a display surface for national occasions. For comparison with its regional neighbours, see the tallest building in Taipei and the count of countries in Asia.
