Two traditional folk dancers performing in Teheran, Iran. (Photo by Keystone Features/Getty Images). 25th January 1961

Visitors to Castle Combe take photographs in the village that was recently featured in Steven Spielberg's latest film, the wartime drama, War Horse, on January 10, 2012 near Chippenham, England. (Photo by Matt Cardy/Getty Images)

People look at French artist Clement Briend's photographic light installation “Divine Trees”, which features images of divine figures highly revered in Asian cultures projected on trees towering over bystanders, during a media preview of the Singapore Night Festival in Singapore August 21, 2014. The Singapore Night Festival begins on Friday. (Photo by Edgar Su/Reuters)

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)

One part of “Celestrial Texts – Heavenly Tweets” by Laine Hogarty is seen as part of the “Hidden” annual sculpture exhibition at Rookwood Cemetery on September 15, 2014 in Sydney, Australia. Located in the suburb or Rookwood in Western Sydney Rookwood cemetery is the largest necropolis in the southern hemisphere. The Annual “Hidden” exhibition features works by local artists. (Photo by Mark Kolbe/Getty Images)

The annual Sculpture by the Sea exhibition in Sydney features dozens of sculptures on Bondi and Tamarama beaches and along the coastal path between them. The free outdoor exhibition, now in its 18th year, stretches for 2km along the coastline and includes work by artists from 16 countries. It runs from 23 October to 9 November 2014. Here: “Breaching” by Michael Greve is displayed during the 2014 Sculptures by the Sea exhibition at Marks Park on October 23, 2014 in Sydney, Australia. (Photo by Cameron Spencer/Getty Images)

An employee at Christie's auction house examines a complete sub-fossilised elephant bird egg on March 27, 2013 in London, England. The elephant bird egg is expected to fetch 30,000 GBP when it features in Christie's “Travel, Science and Natural History” sale, which is to be held on April 24, 2013 in London. (Photo by Oli Scarff)

Turkish artist Nezaket Ekici performs a live art performance entitled 'Emotion in Motion' on the first day of Art Basel 2015, Hong Kong, China, 13 March 2015. The Hong Kong show of Art Basel features 233 galleries from 37 countries and territories, presenting works ranging from the Modern period of the early 20th century to the most contemporary artists of today, according to the official press release. (Photo by Alex Hofford/EPA)