JUNG YEON-JE/AFP/AFP/Getty Images
Fireworks celebrate the opening of Lotte World Tower in Seoul on April 2, 2017.
Lotte World Tower
The cloud-piercing skyscraper is currently the 5th tallest tower in the world.
Courtesy of Kohn Pedersen Fox Associates
At 555 meters tall, the 123-floor building dwarfs the city's next highest building, Three IFC Office Tower, by nearly 300 meters. It is also home to the highest glass-bottom observatory at 478 m (1,568 ft).
Lotte World Tower
Designed by Kohn Pedersen Fox Associates, the tower has a tapered shape that's inspired by Korean art and cultural aesthetics.
Lotte World Tower
The Sky Shuttle double-decker elevator set two new records for being the tallest and fastest of its kind.
Lotte World Tower
The elevator zips guests from the basement to the observation deck on the 121st floor in 60 seconds, or at a speed of 10 meters per second.
Lotte World Tower
Inside the lift cabins, it feels like a video game -- 15 OLED displays present a virtual tour of Seoul during the 60-second ride.
Lotte World Tower
Made by American elevator manufacturer Otis, the lift comprises two attached cabins stacked on top of each other, simultaneously carrying 54 passengers in each cabin.
Lotte World Tower
The expansive view overlooks the Seoul cityscape and Cheonggyecheon River, which flows through the heart of the city.
Lotte World Tower
From the top, visitors can see all of Seoul and as far as the Yellow Sea, to the west of South Korea's capital. If not for the mountains in the distance, North Korea would be visible on a clear day.
Chung Sung-Jun/Getty Images AsiaPac/Getty Images
Lotte World Tower took six years to construct. It houses 61 elevators and 123 floors containing shopping complexes, offices, and even a "seven star" hotel.
Chung Sung-Jun/Getty Images AsiaPac/Getty Images
The view from Lotte World Tower, stretches 50 kilometers in every direction.
Lotte World Tower
An aerial view of the tower shows its stark vertical contrast, compared with its neighbors.

Story highlights

The 555-meter-tall Lotte World Tower opens setting world records.

The Lotte World Tower double-decker elevator travels at 10 meters per second, making it the fastest of its kind in the world.

The Shanghai Tower's elevator is currently the world's fastest elevator, traveling at 20.5 meters per second.

Experts say the fastest elevator humanly possible would travel at 24 meters per second.

CNN  — 

After six years of construction, the 555-meter-tall (1,820 ft) Lotte World Tower opened in April, setting three world records and redefining the Seoul skyline.

Not only is it the tallest tower in South Korea and fifth highest in the world – dwarfing the Korean capital’s next highest building, Three IFC Office Tower, by nearly 300 meters – it’s also home to the highest glass-bottom observatory at 478 meters (1,568 ft).

But its most impressive feat?

The Lotte World Tower features the world’s tallest and fastest double-decker elevator, the Sky Shuttle, which whisks passengers from the basement to the 121st-floor observation deck in one minute, or at 10 meters per second.

From the top of the half kilometer-tall tower, visitors can survey the edges of Seoul’s vast urban sprawl and the mountainous terrain beyond – only a handful of other skyscrapers in sight.

Elevated design

Lotte hired American elevator manufacturer the Otis Elevator Company to bring its double-deck Sky Shuttle to life.

Courtesy of Kohn Pedersen Fox Associates
Lotte World Tower, Seoul

Consisting of two attached cabins stacked on top of each other, it simultaneously carries passengers to separate floors. Other famous structures featuring this type of technology include the Canton Tower, in Guangzhou; the Petronas Towers, in Kuala Lumpur; the Eiffel Tower, in Paris; and the Burj Khalifa, in Dubai.

Boasting twice the capacity of a conventional elevator – each cabin holds 52 passengers – the tower’s lift directly connects the basement and the observation deck, skipping the floors in between which are full of shopping complexes, offices, and even a “seven star” hotel.

“A double-deck elevator was used because the observatory would be crowded at certain times of day,” Wonixuk Choi, manager of Lotte Corporation, tells CNN.

Inside the lift cabins, it feels like a video game – 15 OLED displays offer a virtual tour of Seoul during the 60-second ride.

Elevating Asia

Opened in April 2017, the Lotte World Tower is Seoul's first supertall skyscraper, and is currently the fifth tallest building in the world.

Height: 555 meters (1819 feet)
Architect: Kohn Pedersen Fox Associates
image courtes of emaar / via aurecon group
A new mega-tall skyscraper aims to be the tallest in the world, upon completion in 2020. "The Tower" will be built on the Dubai Creek Harbor, a massive new tourism development. The Tower will eclipse the Dubai's Burj Khalifa -- currently the tallest building in the world.
Height: 928m (3,044ft)
Architect: Santiago Calatrava
image courtes of emaar / via aurecon group
The expected completion date for The Tower in Dubai is 2020.

Height: 928m (3,044ft)
Architect: Santiago Calatrava
image courtes of emaar / via aurecon group
The building will hold several observation decks in its oval-shaped peak. One deck will offer a 360-degree view of the city.

Height: 928m (3,044ft)
Architect: Santiago Calatrava
Jeddah Economic Company/Adrian Smith + Gordon Gill Architecture
A threat to The Tower's tallest tower ambitions is the Jeddah Tower in Saudi Arabia. This tower is currently under construction and due to top out at 1km at a cost of $1.23 billion.

Height: 3,280ft
Architect: Adrian Smith + Gordon Gill Architecture
istockphoto
Currently world's tallest building, since it was completed in 2010, is the Burj Khalifa. It stands a massive 198 meters (650 feet) above its nearest competitor.

Height: 828m (2717ft)
Floors: 163
Architect: Skidmore, Owings & Merrill
FAYEZ NURELDINE/AFP/AFP/Getty Images
Situated close to the Grand Mosque of the holy city of Mecca, the tower complex is one part of the $15 billion King Abdulaziz Endowment Project, seeking to modernize Mecca and accommodate the ever-growing number of pilgrims.

Height: 601m (1972ft)
Floors: 120
Architect: Dar Al-Handasah Architects
via SL Green Realty Corp
A new tall tower has broken ground in New York City. Named the One Vanderbilt Avenue tower, the building is designed by Kohn Pedersen Fox architects, and construction officially started today. At 1,401 feet tall, upon completion it will be the second tallest building in New York after the One World Trade Center.

Height: 427m (1,401ft)
Architect: Kohn Pedersen Fox
In February, a proposal for a mile-high tower in Tokyo was revealed.
Height: 1,600m (5,250ft)
Architect: Kohn Pefersen Fox Associates and Leslie E Robertson Associates
Kohn Pedersen Fox
The 1,600 meter tower is part of a future city concept named "Next Tokyo 2045," which envisions a floating mega-city in Tokyo Bay.

Height: 1,600m (5,250ft)
Architect: Kohn Pefersen Fox Associates and Leslie E Robertson Associates
DBOX
In December 2015, plans were unveiled for the 1 Undershaft -- a 300m tall building that could become the City of London's tallest building.
Height: 300m (984ft)
Floors: 73
Architect: Aroland Holdings
DBOX
1 Undershaft will sit across the river from London's tallest building, The Shard, which is 9.6 meters taller.

Height: 300m (984ft)
Floors: 73
Architect: Aroland Holdings
Courtesy CIM Group
432 Park Avenue, the tallest all-residential tower in the western hemisphere, opened its doors in December 2015, recently became the hundredth supertall building in the world.

Height: 425.5m (1396ft)
Floors: 85
Architect: Rafael Vinoly, SLCE Architects, LLP
Gensler
Completed in 2015, Asia's tallest building surpasses the Shanghai World Financial Center and the Jin Mao Tower in Shanghai's Pudong district. Estimated to cost $2.4 billion, its completion marked the end of a project in the financial district stretching back to 1993.

Height: 632m (2073ft)
Floors: 128
Architect: Jun Xia, Gensler
STAN HONDA/AFP/AFP/Getty Images
Known as the "Freedom Tower," One World Trade Center stands on part of the site previously occupied by the Twin Towers. It's the highest building in the western hemisphere, and cost $3.9 billion according to Forbes.

Height: 541.3m (1776 ft)
Floors: 94
Architect: Skidmore, Owings & Merrill
Taiwan Tourism
The first skyscraper to break the half-kilometer mark, the world's tallest building between March 2004 and March 2010 is also one of the greenest -- certified LEED platinum in 2011. Designed to withstand the elements, including typhoons, earthquakes and 216 km/h winds, Taipei 101 utilizes a 660-tonne mass damper ball suspended from the 92nd floor, which sways to offset the movement of the building.

Height: 508m (1667ft)
Floors: 101
Architect: C.Y. Lee & Partners
ChinaFotoPress/Getty Image
Construction of Shanghai's third supertall building took 11 years, but the skyscraper dubbed "The Bottle Opener" was met with critical praise and high-end residents when it completed in 2008, including the Park Hyatt Shanghai and offices for Ernst & Young, Morgan Stanley, and BNP Paribas.

Height: 492m (1614.17ft)
Floors: 101
Architect: Kohn Pederson Fox
ANTHONY WALLACE/AFP/AFP/Getty Images
Hong Kong's tallest building has 108 floors -- but walking around it, you'd get a different story. The city's tetraphobia -- the fear of the number four -- means floors with the number have been skipped, and the International Commerce Center is marketed as a 118-story skyscraper.

Height: 484m (1588ft)
Floors: 108
Architect: Kohn Pedersen Fox
Blackstation/courtesy gensler
Standing at 2,074 feet (632 meters) tall, the Shanghai Tower is the world's second tallest building.
Goh Seng Chong/Bloomberg via Getty Images
The joint eighth highest completed skyscraper is still the tallest twin towers in the world. Finished in 1996 and inaugurated in 1999, it's been the site of numerous hair-raising stunts. Felix Baumgartner set a then-BASE jump world record in 1999 by jumping off a window cleaning crane, and in 2009 Frenchman Alain Robert, known as "Spiderman," freeclimbed to the top of Tower Two without safety equipment -- and did so in under two hours.

Height: 451.9m (1483ft)
Floors: 88
Architect: Cesar Pelli
Sun Chen
The architects behind the Burj Khalifa are also responsible for the world's tenth tallest building. Skidmore, Owings & Merrill's Zifeng Tower in Nanjing completed in January 2010 and sits just above the Willis Tower (previously the Sears Tower) in the rankings, eclipsing the SOM-designed Chicago icon by a mere 7.9 meters (26 ft).

Height: 450m (1476ft)
Floors: 66
Architect: Skidmore, Owings & Merrill
Wong Tung & Partners
A hotel and office hybrid, this straightforward supertall building by Wong Tung & Partners in Hunan Province's booming capital city is expected to be completed by 2017.

Height: 452 metres (1,482 ft)
Architect: Wong Tung & Partners
E8xE8
The Suzhou IFS is two meters shy of the Changsha tower.
Height: 450 meters (1476 feet)
Architect: Kohn Pedersen Fox Associates
Pei Cobb Freed & Partners
The World One skyscraper in Mumbai will be as tall as the Willis Tower, the second tallest building in North America, and will be one of the world's tallest residential structures.

Height: 442 meters (1450 feet)
Architect: Pei Cobb Freed & Partners
DLN Architects
This design mimics and simplifies the neo-Gothic spires of an earlier skyscraper boom, à la the Woolworth and Empire State Buildings.
Height: 383 meters (1,257 ft)
Architect: Dennis Lau & Ng Chun Man Architects & Engineers
Kohn Pedersen Fox Associates
Kohn Pedersen Fox is back with this 90-story residential building. Zigzagging cuts in the curtain-wall break up the monotony of yet another boxy tower.

Height: 372 metres (1,220 ft)
Architect: Kohn Pedersen Fox

Asia has made a name for itself in ground-breaking elevator technology in recent years.

In 2016, the Shanghai Tower opened, unveiling the fastest elevator in the world.

The Mitsubishi-designed lift runs at an incredible 20.5 meters per second (67 ft/s).

Standing at 2,074 feet (632 meters) tall, a fast lift was always going to be necessary for the world’s second tallest tower.

Also in China, Hitachi last summer unveiled the world’s second fastest elevator in Guangzhou’s tower CTF, which stands at 1,739 feet tall.

Its lift zooms from floors zero to 95 in an incredible 45 seconds – or 20 meters per second (65 ft/s).

Inside the elevator cabin, an indicator shows passengers how fast they are going, perhaps to prove that they aren’t being cheated.

03:20 - Source: CNN
Race to the top

A high-tech air pressure adjustment system that protects ears from popping and blocks any uncomfortable G-force backlash means this lift is so smooth it’s hard to believe it’s the world’s second fastest.

“The elevatoring strategy required us to bring in high volumes of people … and the client made a huge investment to try to make sure that happened quickly, “Forth Bagley, principal architect at KPF, which designed the CTF tower, tells CNN.

Lift me up

Getting people around ever-taller towers with increasing efficiency is a common concern.

Reaching 1km into the sky, the Jeddah Tower in Saudi Arabia will be the world’s tallest building when completed in 2019.

A building so tall, naturally, requires an exceptionally fast elevator.

Chow Tai Fook Enterprises Ltd
The CTF Tower in Zhujiang New Town in Guangzhou, Southern China.

Finnish maker Kone has risen to the challenge, developing the “ultrarope” elevator, which uses a carbon-fibre cable strong enough to power a lift more than 1km in length – previously, about 500km was the maximum length possible for a lift cable.

One third of the weight of traditional lift ropes, it also makes super speeds a reality.

The ultrarope lift will travel at “over 33 feet per second”, and “reach the highest liveable floor in the world in 52 seconds,” according to Kone.

When finally unveiled, it could easily be faster than Lotte World Tower’s creation. However Albert So, an expert in elevator engineering, believes lift technology can’t get much faster.

“I predict the maximum speed of a vertical lift cabin cannot be more than 79 feet per second,” he says. “This is not because we can’t make lifts that go faster than this, but because of the air pressure.”

If a lift traveled faster than this, he says, it wouldn’t give passengers enough time to acclimatize to the air pressure on the top floor.

Engineers would need to pressurize the entire building, like an airplane cabin.

Lifts that move sideways?

Perhaps the most exciting innovation in lift technology is coming from German transport firm Thyssenkrupp.

By using magnetic levitation, or “maglev” technology – which uses magnetic fields rather than elevator cables to propel cabins – the company is proposing elevators that move both vertically and horizontally.

Wolfgang Traeger
This floating wooden pavilion is the Pavillion of Reflections in Zurich. It was revealed as part of Manifesta, an annual contemporary art biennial.
Wolfgang Traeger/courtesy manifesta
The wooden structure is a collaborative project between 30 architecture students from ETH in Zurich and design firm Studio Tom Emerson.
Wolfgang Traeger/courtesy manifesta
Described as an "urban island," the floating structure is intended for leisurely use, and features an open-air cinema.
courtesy White Arkitekter
The "Sida Vid Sida" ("side by side") building is a proposed project by Swedish architects White Arkitekter.
courtesy White Arkitekter
The proposed design won an architecture competition in the city of Skelleftea. There were 55 entries from 10 countries.
courtesy White Arkitekter
The design was selected for its use of wood as a building material, as it pays tribute to Skelletea's rich local timber industry.
courtesy White Arkitekter
The building is expected to be completed in 2019.
courtesy plp architecture
Oakwood Tower is a proposed structure by PLP Architecture and Cambridge University's Department of Architecture.
courtesy plp architecture
At 80 stories high, it would be London's first wooden skyscraper, and another addition to the growing trend for structures made entirely of timber.
Lendlease
The Forte in Melbourne was completed in 2012, and is a 10-story structure built entirely of wood.
Lendlease
For two years, the 104-foot tall structure was the tallest wooden building in the world.
Snølys
That title was soon taken by the Treet in Norway.
Morten Pedersen
Treet was completed in 2014, and is 14 stories tall.
Courtesy of MGA
The Wood Innovation and Design Center (WIDC) is located in the province of British Columbia in Canada.
Courtesy of MGA
The building is a hub for wooden design education and research.
dean irvine/cnn
In Bali, the 18-home Green Village is constructed almost entirely of bamboo.
dean irvine/cnn
"This is the future. It's pure architecture ... to breathe fresh air and touch nature, that's everything," says architect Defit Wijaya.
CRG Architects
CRG Architects proposed a skyscraper made entirely of bamboo at the World Architecture Festival in 2015.
crg architects
Bamboo was recently recognized by the United Nations as a green building material that can help combat climate change.

This type of elevator would be slower, at least initially, but it could increase travel efficiency throughout a sprawling building.

“I think this is our future,” says So. “Our elevators will become more like a chess board, the pieces on the board moving around the building.”

So acknowledges that governments around the world remain unconvinced of horizontal elevators’ safety credentials, but says their introduction is only a matter of time.

“There is no practical value of building tall, when a tall building becomes slimmer as it gets taller,” So says. “Most of the area at the top of the building is used for the elevator.”

A bigger building with a horizontal elevator is a better use of space, he says.