Images created with Post-it notes are seen in the windows of offices at 75 Varick Street in lower Manhattan, New York, U.S., May 18, 2016, where advertising agencies and other companies have started what is being called a “Post-it note art war” with employees creating colorful images in their windows with Post-it notes. (Photo by Mike Segar/Reuters)

Head of Global Marketing, Volkswagen Group Luca de Meo speaks onstage during the U.S. reveal of the 2012 Volkswagen Beetle at Pier 36 on April 18, 2011 in New York City. (Photo by Michael Loccisano/Getty Images for Volkswagen)

Alexa Cinton marches up Fifth Avenue in the Puerto Rican Day Parade on June 12, 2011 in New York City. The Puerto Rican Day Parade draws hundreds of thousands and was first celebrated in New York City in 1958. (Photo by Mario Tama/Getty Images)

People walk past a downed tree in Central Park on October 31, 2011 in New York City. Central Park may lose 1,000 trees following a freak October snowstorm while the park only lost 125 trees due to Hurricane Irene. (Photo by Mario Tama/Getty Images)

A visitor poses inside a three story upside-down family sized house at the Huashan Creative Park in Taipei, Taiwan April 7, 2016. Over 300 square meters of floor space of the upside-down house, filled with home furnishings, was created by a group of Taiwanese architects at a total cost of around US$600,000 and took 2 months to complete, according to the organisers. (Photo by Tyrone Siu/Reuters)

Barneys New York launches Gaga's Workshop with the inflation of the Gaga Spider Balloon at the corner of 23rd and Broadway on November 21, 2011 in New York City. (Photo by Neilson Barnard/Getty Images for Barneys New York)

This image taken from video provided by TVBS shows a commercial airplane clipping an elevated roadway just before it careened into a river in Taipei, Taiwan, Wednesday, February 4, 2015. The ATR-72 prop-jet aircraft had 58 people aboard. (Photo by AP Photo/TVBS)

These are the ambitious plans which suggest skyscrapers of the future may house an entire city. The Endless City project is an award-winning proposal by sure Architecture, who propose turning skyscrapers into complete ecosystems. London is the proposed city for the mixed-use tower – which would feature huge ramps linking different sections of the structure. The company, whose design won the SkyScrapers and SuperSkyScrapers Competition, insist the structure would be a great space-saver in dense cities which have previously spread outwards rather than upwards. (Photo by Caters News)