The buildings which can beat Tallest Building in the world

The Burj Khalifa, currently the tallest tower in the world, with 2716.5-feet of aluminum and steel, and its 26,000 hand-cut glass panels. The Burj Khalifa blows away the next-nearest skyscraper, which is Taiwan's 1670-foot Taipei 101, and the building has even surpassed ultra-tall, ground-cable-supported radio antennas. 

Architects' vertical leapfrogging, however, isn't likely to stop at the Burj Khalifa. While the tower will be a tough one to beat, it is likely to remain at the pinnacle for only about another half-dozen years. Developers around the world have proposed numerous new skyscrapers. Some projects have leapt off the drawing boards, though plans for many record-breaking towers have been scuttled because of the global economic spasms of the past couple years. (The original name of the Burj Khalifa, the Burj Dubai, was changed at the last minute to recognize United Arab Emirates president Sheik Khalifa bin Zayed al-Nahyan, who as emir of Abu Dhabi gave struggling Dubai a $10 billion bailout last month.) 

So what buildings could be the next to rise up and steal the Burj Khalifa's crown? Here are eight future contenders. 

1. Burj Mubarak al Kabir

Location /// Madinat Al Hareer (City of Silk), Kuwait
Projected Height /// 3284 ft

(Photograph by Eric Kuhne and Associates)

This mammoth structure will rise to exactly 3284 feet, or 1001 meters. The height, in meters, is an allusion to the classic collection of Middle Eastern and South Asian folk tales One Thousand and One Arabian Nights, says London-based architect Eric Kuhne, whose firm designed the tower. To break the kilometer-high mark (which is 3281 feet), the $7 billion-plus Mubarak al Kabir will have three interlocked towers that support the overall structure. These towers, or "blades," pinwheel about a triangular central shaft that holds elevators and mechanical equipment. Each blade twists 45 degrees as it rises, for strength, and expands slightly at the top. This Kuwaiti landmark will therefore place more mass and usable space near its zenith compared to other towers, says Kuhne, to avoid the structure having too thin and flexible a tip. To dissipate high-altitude, tower-buffeting gales that could blow at 150 miles per hour, the Mubarak al Kabir will see the first architectural deployment of vertical ailerons—the normally horizontal flaps airline passengers see on a plane's trailing wing edge that help counter wind disturbances. "They will look like continuous ribbons running vertically along the six leading edges of the three blades," Kuhne says. "As [the ailerons] are constantly moving, and catching the sun while they adjust, sunlight will glint off their surfaces. It will add a gentle rippling reflection to the edges of the blades that will add dynamic sparkle to the tower," Kuhne says. The Burj Mubarak has a projected completion date of 2016. 

2.1 Dubai

Location /// Dubai, United Arab Emirates
Projected Height /// Three towers: 1969 ft, 2625 ft and 3281 ft

(Photograph by Adrian Smith + Gordon Gill Architecture)

Building higher also means building wider. That is why the 3280-foot 1 Dubai will be built with three towers. "What tends to happen is as these buildings get taller, the base needs to be wider, but it gets to the point that it's just too wide to be a single building and you start to pull things apart or separate them," says Peter Weismantle, director of supertall building technology at Adrian Smith and Gordon Gill Architecture. The smallest tower of 1 Dubai will come in at around 1970 feet and the tallest at about 3280. All three emerge from a tripedal base architects call the saddle. A canal will flow between 1 Dubai's three legs, letting boats sail underneath. Further support for the towers comes from the connecting skybridges where tower residents will be able to congregate. Designers envision building the skybridges at the saddle and then using a jacking mechanism to hoist them into place. Clearing the site for the project began in 2008 but has since been put on hold thanks to the state of the world economy. If and when construction begins in earnest, 1 Dubai will take somewhere between seven and 10 years to complete. 

3.Miapolis

Location /// Miami, USA
Projected Height /// 3000 to 3281 ft

(Photograph by Kobi Karp/Thornton Tomasetti/EDSA/Miapolis)

The 160-story Miapolis will rise nearly 3300 feet on Watson Island in Biscayne Bay, just west of Miami Beach and east of downtown Miami. The $22 billion Miapolis complex will host an indoor amusement park, luxury condos and apartments, office space, a performing arts center, and a marina. With Miapolis, planners hope to demonstrate the potential economic benefits of high-profile real estate: developers say it could bring in nearly a billion in annual tax revenue and pump over twice that into the local economy as visitors flock to South Florida's newest attraction. For now, the project remains on the drawing board at architectural firm Kobi Karp, and there is no shortage of artist's impressions of the many facets of Miapolis. The designers want the complex to be environmentally responsible and intend to have the building receive a LEED Platinum rating by the U.S. Green Buildings Council. Further information about Miapolis is scant for now as developers are tight-lipped about the project, though lead developer Guillermo Socarras says he will be announcing new details in a few weeks. Meanwhile, Socarras is in talks with the Federal Aviation Administration about getting clearance on Miapolis' soaring height, given the proposed site's proximity to Miami International Airport. 

4.Nakheel Tower

Location /// Dubai, United Arab Emirates
Projected Height /// 3281 to 4593 ft

(Photograph by Woods Bagot / Nakheel Harbour & Tower)

This cylindrical megatower has eight spires that come to a point at the building's peak. Though an official target height has not been revealed, the Nakheel Tower is likely to crest 3280 feet. Its designers, the international firm Woods Bagot, aim for the Nakheel Tower to be the first true realization of a vertical city. Over 15,000 people will live, work and socialize in this spire with a ground footprint the size of a New York City square block. The placement of support columns is based on a radially symmetrical 16-point star pattern and is inspired by Arabic patternmaking. The pattern makes engineering sense because a symmetrical building bears the load evenly among its structural units, according to a 2009 case study on the Nakheel Tower published in the journal of the Council on Tall Buildings and Urban Habitat. The trickiest part about designing the Nakheel Tower, according to the study, was dealing with so-called vortex shedding from winds, which can cause damaging vibrations. Instead of funneling wind around its metal and glass skin, the Nakheel Tower takes the uncommon approach of having large gaps in the midst of the building, with a double set of slots that let gales pass right through. Every 25 floors or so, big disk-like skybridges bind the towers together and serve as village squares for high-rise dwellers, as in 1 Dubai. Also as in 1 Dubai, the Nakheel Tower's completion date has been held up because of unfavorable market conditions, though some early construction work did get underway before the stall. A completion date has not been announced and the project may never resume. 

5.Sky City 1000

Location /// Tokyo, Japan
Projected Height /// 3281 ft

(Photograph by Takenaka Corporation)

The Takenake Corporation proposed Sky City 1000 back in 1989 to tackle Tokyo population-density problems. Tokyo-like congestion prompts a demand for green space and office space that vastly exceeds supply, and also introduces a host of environmental and social issues, from pollution to uncomfortably packed commuter trains. Takenake's solution: Build up—way up—and place green spaces in the sky. "The feature of our proposal was making artificial land in the air," says Masato Ujigawa, manager of the engineering department at Takenaka. To achieve this, Takenake will first start with a base that is 1300 feet per side, a footprint that equates to several city blocks (Burj Khalifa's triangular footprint is just 300 feet or so). Then, in accordance with its name, Sky City 1000 will rise a full thousand meters (3281 feet), consisting of 14 levels stacked on top of one another. Each level will act as its own "town," with a park-like plaza area in its center ringed by residences, schools and businesses. The structure would hold 10,000 homes and be used in some capacity by 130,000 people. Construction has not begun on Sky City 1000 since Japan's population has begun shrinking as of 2005, Ujigawa says. Nevertheless, Ujigawa says that ideas originally espoused by the Sky City 1000 project have since been used in more conventional construction. These include concrete reinforced with carbon fibers instead of iron to cut down on weight, and self-contained water-service systems in buildings that treat sewage and reclaim water. 

6.Bionic Tower

Location /// (Originally Proposed For) Shanghai, China
Projected Height /// 4029 ft

(Photograph by Eloy Celaya)

The roughly $15 billion Bionic Tower will break from traditional engineering principles, introducing radical design elements for the 4029-foot-tall tower, according to Eloy Celaya, an architect with ECE Arquitecturas and one of three principal Spanish designers of the Bionic Tower. Instead of vertical foundations, Celaya envisions a "floating foundation" similar to a tree's roots, with a tangle of many hundreds of anchors in the ground. For supportive, criscrossing trusses, the Bionic Tower will draw inspiration from bird bones, which are light and hollow. The twelve stacked neighborhoods within this vertical megalopolis will receive water, energy and other supplies by means of 92 vertical columns (much like the xylem and phloem transport systems in vascular plants), which will double as structural supports. Though the concept for the Bionic Tower was originally pitched to Shanghai, China about a decade ago, at present the prospects for this tower being erected someday are iffy. 

7.Kingdom Tower

Location /// Jeddah, Saudi Arabia
Projected Height /// 3281-plus ft

This is a photo of the existing Kingdom Centre in Riyadh. Images of the Kingdom Tower in Jeddah are not yet publicly available. (Photograph by Ameen Mohammad)

This skyscraper was initially billed as the Mile-High Tower in 2008, though the record-setting height ambitions have since been cut by nearly 2000 feet. Updated design plans have not yet been revealed for the Kingdom Tower, but the winner of a design contest between Skidmore, Owings & Merrill and Adrian Smith and Gordon Gill Architecture should be announced in a few weeks. Marshall Gerometta, of the Council on Tall Buildings and Urban Habitat, the group that certifies supertall building heights, says that the Kingdom Tower probably is the best bet in the near term to overtake the Burj Khalifa. Funding appears secured for this building, which will be the centerpiece of a new $27 billion planned urban area in Jeddah, Saudi Arabia, overseen and financed by the Kingdom Holding Company. The first mile-high setup called for the creation of two stabilizing mini-towers to support the main tower. The mini-towers, at nearly 1000 feet each, about the height of the Eiffel Tower, will be dwarfed by the central spire. Many supertall building tops have an "expected" lateral movement of 10 feet or so, and to mitigate this swaying effect, a massive, computer-controlled object called a damper will be placed within the mile-high structure. What the eventual building will look like and how it will be engineered remain open questions, though Gerometta says he heard the Kingdom Tower was going to represent "a new generation of skyscrapers." 

8.Millennium Challenge Tower

Location /// TBD
Projected Height /// 6076 ft

(Photograph by Omero Marchetti Workshop)

This concept tower has also been referred to as the Al Jaber Tower in accordance with its possible placement in Kuwait. This tower would soar to a full nautical mile, 1852 meters, or over 6000 feet. Italian architect Omero Marchetti, the founder of the Millennium Challenge 1852 project, says "to reach [a marine mile] you cannot use concrete, orthogonal grids, traditional systems, mortars, [and] cranes." The building would dispense with right angles and perpendicular planes as these structural engineering norms make large quantities of cast iron and concrete "follow an unnatural and twisted geometry," Marchetti says. He has instead looked to the hexagonal matrices of snowflakes, which as structurally supported objects combine high volume with low weight. Marchetti says that currently three groups of investors in different parts of the world are interested in making the Millennium Challenge Tower a reality, a step he believes is necessary to make a sustainable planet. "I think we have not a second chance, or if you prefer, we have not a second planet," Marchetti says. "I tell you that this is the future, which is up to us to capture now."