Photos of Edward Snowden, a contractor at the National Security Agency (NSA), and U.S. President Barack Obama are printed on the front pages of local English and Chinese newspapers in Hong Kong in this illustration photo June 11, 2013. Snowden, who leaked details of top-secret U.S. surveillance programs, dropped out of sight in Hong Kong on Monday ahead of a likely push by the U.S. government to have him sent back to the United States to face charges. (Photo by Bobby Yip/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)

The old church of Geamana village is seen partially submerged by polluted water tainted with cyanide and other chemicals near Rosia Montana, central Romania, March 24, 2014. (Photo by Bogdan Cristel/Reuters)

The 2012 Magic Art Special Exhibition Of China is now open at the Hangzhou Peace International Exhibition and Conference Centre of the Chinese city of Hangzhou.

Photo: Visitors poses with a 3D painting during a show featuring over 50 such works in China on July 20, 2012. (Photo by Associated Press)

The Tribute in Light is seen behind the Empire State Building on September 10, 2011 in New York City. The Tribute in Light is an art installation honoring those who perished in the 9/11 attacks. New York City and the nation are preparing for the tenth anniversary of the terrorist attacks on lower Manhattan which resulted in the deaths of 2,753 people at the World Trade Center. (Photo by Mario Tama/Getty Images)

“The harp seal or saddleback seal is a species of earless seal native to the northernmost Atlantic Ocean and adjacent parts of the Arctic Ocean. Newborn pups weigh around 11 kilograms (24 lb) and are 80–85 centimetres (31–33 in) long. After birth, the mother only feeds that pup. During the 12 day nursing period, the mother does not eat, losing up to 3 kilograms (7 lb) per day. Harp seal milk contains up to 48% fat, so pups gain over 2.2 kilograms (4.9 lb) per day. During this time, the juvenile's “greycoat” grows in beneath the white neonatal coat, and it weighs 80 pounds (36 kg)”. – Wikipedia

Photo: A harp seal pup lies on an ice floe in the Gulf of Saint Lawrence March 24, 2008 in Charlottetown, Canada. (Photo by Joe Raedle/Getty Images)

A creature bathes at the Robolights art installation by Kenny Irwin Jr. in Palm Springs, California December 15, 2014. The installation consists of hundreds of whimsical robot and other themed sculptures created from recycled materials including golf carts, kitchen appliances and microwaved smart phones, and is open to the public each holiday season on the sprawling Irwin family property. (Photo by David McNew/Reuters)

An employee holds a plant with roots at the Plant Advanced Technologies (PAT) company greenhouse in Laronxe near Nancy, Eastern France, June 19, 2015. The farmers employed at the site in Laronxe are growing plants in a special way with a view to “milking” them for use in medicines, cosmetics and agrochemicals. Several major brands, including Germany's BASF and France's Chanel, have teamed up with Plant Advanced Technologies (PAT) in the hope of securing privileged access to the so-called “biomolecules” it extracts through the use of a patented technique. (Photo by Vincent Kessler/Reuters)