This undated photo provided by the Ford Motor Co. shows the 1948 Lincoln Continental Cabriolet V12. Thirteen years after the last Continental rolled off a Michigan assembly line, Ford Motor Co. is debuting the new Continental in concept form at the New York Auto Show on Monday, March 30, 2015.The production version goes on sale next year. (Photo by AP Photo/Ford Motor Co.)

A Saudi soldier fires a mortar towards Houthi movement position, at the Saudi border with Yemen April 21, 2015. (Photo by Reuters/Stringer)

The civilised world lies on its knees, a sickness wracking its body. The affliction causes a necrotising of tissues so perfectly uniform in distribution that victims take on the appearance of corpses long before death occurs due to organ failure or secondary infections. ...

A visiitor bungee jumps during an outdoor festival to celebrate German Unity Day on the 21st anniversary of German reunification on October 3, 2011 in Berlin, Germany. German Unity Day is a national holiday and marks the day West Germany and East Germany were reunited in 1990 following the collapse of the Iron Curtain. (Photo by Adam Berry/Getty Images)

A man irrigating a rice paddy field using a traditional method. (Photo by Fox Photos/Getty Images). Japan, circa 1938

(L-R) Zandea,18, and Jessica, 21, pose showing off their clothing backstage during a show featuring OPT jeans December 8, 2011 in Yangon, Myanmar. (Photo by Paula Bronstein /Getty Images)

Children feeding the birds in this Victorian Christmas greetings card. (Photo by Hulton Archive/Getty Images). Circa 1885

An installation consisting of a series of bird boxes is displayed in a tree in Duncan Terrace Gardens in Islington on March 24, 2011 in London, England. The boxes by artists Bruce Gilchrist and Jo Joelson of “London Fieldworks”, were designed to reflect the architecture of the Georgian terraces and flats that surround the park in the community gardens. (Photo by Dan Kitwood/Getty Images)