The winning four were chosen from a total of 123 entries (up from last year's competition, which featured 88 entries), and will eventually be whittled down to just one when the CTBUH declares its pick for world's top tall building of the year in November.
Noting that the tower is a new landmark for New York City, and a building of significant importance worldwide, CTBUH declared Skidmore, Owings & Merrill's One World Trade Center the best new tall building in the Americas.
One World Trade Center comprises 94 above-ground floors and is deemed to measure exactly 1,776 ft (541 m), in honor of the year that the United States made its Declaration of Independence from Great Britain. Located in the northwest corner of the World Trade Center site, the tower boasts a LEED Gold green building certification and was officially completed in 2014.
Asia and Australasia
Singapore's CapitaGreen building, by Toyo Ito and RSP Architects received the nod for the Asia and Australasia category. Measuring 794 ft (242 m), the office tower is the 11th tallest in the island city state.
Some 55 percent of the perimeter of the building's facade is covered in greenery. CapitaGreen's facade also has an outer layer of frameless glass and an inner envelope of double-glazed floor-to-ceiling glass, which is said to combine to reduce solar heat gain by up to 26 percent. Furthermore, at the top of the tower, a petal-shaped scoop draws in cool air from above, which is then channeled around the entire building, cooling the interior naturally.
Europe's winning entry also boasts ample greenery, and Milan's impressive Bosco Verticale (or Vertical Forest) residential project lives up to its name, with the twin towers boasting some 480 large and medium sized trees, 250 small trees, 11,000 plants and 5,000 shrubs. Designed by architects Boeri Studio, the larger of the two measures 382 ft (116 m), while the smaller rises to 279 ft (85 m).
According to CTBUH, the extensive greenery improves air quality by filtering out dust and sequestering carbon, while also reducing noise pollution.
Middle East & Africa
The Burj Mohammed Bin Rashid Tower, by Foster + Partners, is located in Abu Dhabi and rises to a total height of 1,251 ft (381.2 m). Located in the center of the city, the residential tower's smooth reflective facade is designed to require minimal maintenance, despite the dusty environment, and layers of internal shading control glare and heat gain.
CTBUH says that the building's glass cladding creates a mirage effect that reflects its geographic context.
For more on skyscrapers, be sure to check out Gizmag's own take on the current – and future – tallest buildings in the world.