Lotte World Tower

Lotte World Tower, is a 123-story, 555 m supertall skyscraper, located in Sincheon-dong, Songpa-gu, Seoul, South Korea. It is the sixth-tallest building in the world, the tallest in OECD countries, and also the first in South Korea to be over 100 stories tall.

It was the fourth-tallest in the world when completed in 2016. The tower opened to the public on April 3, 2017. Haeundae LCT The Sharp in Busan is the second-tallest building in the country.

A "Sky Bridge Tour" is located on the roof of Lotte World Tower at 541 m, which is the total height of One World Trade Center in New York City, the tallest building in the United States.

History
After 13 years of planning and site preparation, the tower gained final approval to start construction by the government in November 2010 and the first groundbreaking activities of piling and frame assembly were observed at the construction site in March 2012.

On December 31, 2015, the LED-pixels of the façade displayed the number "2016".

On April 3, 2017, Lotte shot off fireworks to celebrate the tower's official opening.

On January 1, 2018, Lotte shot off fireworks with a LED laser show for seven minutes to celebrate New Year's Day and the 2018 PyeongChang Winter Olympics.

Design
On March 17, 2016, before the final phase of external construction, the Diagrid lantern-shaped roof structure was completed. The roof structure was constructed with steel counterparts that are each 12 m and weigh 20 tons. The counterparts were made up of bent metal panels that are 6 cm thick. The roof structure itself is 120 m high and covers floors 107–123. Approximately 3,000 tons of steel parts, a high-precision 64t tower crane and GPS alignment systems, as well as welding technicians, were used in the construction of the roof.

The roof structure is engineered to withstand its weight without reinforcing pillars, endure earthquakes up to a magnitude of 9 under the Richter magnitude scale, and winds up to 80 m/s.

The exterior of pale-coloured glass draws inspiration from Korean ceramics and features accents of metal filigree.

Floor plans
Seoul Sky occupies the top seven levels. Floors 117–118 are the entrance and view floor, including a glass floor and sky show on 118. Sky Friends Cafe and the sky terrace are located on floors 119–120. Seoul Sky Cafe and a souvenir shop are on floors 121–122, and the premium lounge bar, 123 lounge, is on the top floor at 499 m.

The observatory charges an admission for entry. The skylight of Seoul Sky was the highest glass floor observatory as of the tower's completion. The tower and One World Trade Center have concluded an operation and technical service agreement. The operating hours of the observatory are divided into two periods. From Sunday to Thursday, it is open from 10:30 AM to 10:00 PM. On Fridays, Saturdays, and public holidays, it is open from 10:30 AM to 11:00 PM.

Safety issues
In 2013 and 2014, three construction workers died during the construction of the tower, and an executive director of Lotte's construction arm was given a suspended sentence of eight months in prison in 2016 for his role in neglecting safety measures at the site. In December 2014, the Seoul city government ordered the mall and cinema complex at the base of the tower, which opened before completion of the tower, to be closed for five months after water was found leaking from an internal aquarium. Independent engineers who assessed the building found that the issues bore little relation to the overall structural integrity of the building and the mall and cinema complex reopened in 2015.

Illegal entries and climbing
In 2016, two men from Ukraine illegally climbed the under-construction Lotte World Tower via its stairs, and one of them free solo climbed up the crane to the top. Following the climb, Lotte World Tower released posters with the photos of the two and banned them from the building.

On June 12, 2023, a 24-year-old British man illegally climbed the tower without ropes from the ground. The building security discovered him on the 42nd floor at 192 m above ground at 7:50 am. While he was taking a break on the 72nd floor, the police stopped him on the 73rd floor at 313 m above ground by using a building maintenance unit at 8:47 am. After his arrest, he said that he had planned the climb for six months.

Cherry Blossom Festival
Even when Lotte World Tower was under construction, there were many people who celebrated the cherry blossom festival on April 10–12, 2015, and it is still possible to celebrate after its completion. In 2017, the Seokchon Lake cherry blossom festival was held from April 1 to April 9. It was held at Seokchon Lake waterfront stages(East and West Lake), Seoul Playground, and Gallery Sue, and was free of charge. Recently, it was held from April 5–9 in 2023, and March 27–31 in 2024.

Fireworks Festival
The World Tower was completed in December 2016, and the fireworks festival was held for the first time on April 2, 2017. The venue is in the Lotte World Tower and Seokchon Lake area and is free of charge. There was a K-POP concert from 7:30 pm to 9 pm, a Lotte World Tower fireworks show from 9 pm to 9:10 pm, and recreation and giveaways from 9:10 to 9:30 pm. The Lotte World Tower Fireworks Show was held again on May 4, 2019, and was accompanied by an eight-hour public broadcast event in collaboration with CBS Music FM. From 2020 to 2022, it is not progressing due to COVID-19.

Citizen's evaluation
In 2014, Lotte held a 10-day pre- opening in the second week of September, commissioning experts to diagnose the structural safety of the building and offering preview tours to the public, which was generally well received, although it was pointed out that Lotte's actions were merely a publicity stunt for the building. The building under construction at the time received negative reviews for being dangerous and poorly constructed, but Lotte Engineering&Construction rehabilitated it, and in 2016 it received positive reviews for being safe and well designed for earthquake resistance. In 2017, Seoul residents rated the second Lotte World as safe and well designed.