Chinese artist Kong Ning walks in her costume made of hundreds of orange plastic blowing horns during her art performance raising awareness of the hazardous smog in front of the Drum tower in a historical part of Beijing on a very polluted day December 7, 2015. Kong, whose works include themes related to China's air pollution problem, named her new performance “The Orange Horns Bride Marries the Blue Sky” and presented it dressed in orange, the colour of the second highest pollution alert level issued again in Beijing as hazardous smog blankets the capital. (Photo by Damir Sagolj/Reuters)

A leopard seal feeds Paul Nicklen a penguin. (Photo by Paul Nicklen/National Geographic). Antarctic Peninsula, 2011

A indigenous man from the Tabajara tribe is seen in Tocantins river before the I World Games for Indigenous People in Palmas, Brazil, October 21, 2015. (Photo by Ueslei Marcelino/Reuters)

An autumn leaf sticks to a bench near the Bishops Castle near Wells Cathedral on November 1, 2011 in Wells, England. According to a number of nature watchers the autumn colours are currently reaching their peak following an unusually warm September and October which has led to trees holding onto their leaves longer than normal. (Photo by Matt Cardy/Getty Images)

Anne Hathaway arrives for the premiere of Twentieth Century Fox & Blue Sky Studios' “RIO” on April 10, 2011 in Hollywood, California. (Photo by John Sciulli/Getty Images)

German field telegraph operators at work in Warsaw. (Photo by Hulton Archive/Getty Images). 1st October 1914

A model prepares backstage ahead of the Amber & Thomas show during Rosemount Australian Fashion Week Spring/Summer 2011/12 at Overseas Passenger Terminal on May 3, 2011 in Sydney, Australia. (Photo by Ryan Pierse/Getty Images)

A model showcases designs on the catwalk during Beijing Institute of Fashion Technology and Taiwan Shin Chien University Graduates Collection show of China Fashion Week A/W 2011 on March 25, 2011 in Beijing, China. (Photo by Feng Li/Getty Images)