HRP-4C, a five-foot humanoid robot developed at Japan's National Institute of Advanced Industrial Science and Technology, sings and dances with performers at the Digital Contents Expo in Tokyo on October 17, 2010. The robot runs entertainment software called Choreonoid, a name formed from the words “choreograph” and “humanoid”. (Yoshikazu Tsuno/AFP)

A colourful sky before sunrise on Whitley Bay beach on December 21, 2015, as December could be the mildest across a large part of England since records began more than 350 years ago, forecasters have said. (Photo by Owen Humphreys/PA Wire)

A Syrian boy looks through a gate as others wait to cross into Syria at Oncupinar border crossing in the southeastern city of Kilis, Turkey February 11, 2016.. (Photo by Osman Orsal/Reuters)

A man walks through the morning mist in a park in Rozzano, near Milan, northern Italy, Thursday, December 17, 2015. (Photo by Antonio Calanni/AP Photo)

An aircraft passes over houses at it lands at Heathrow Airport near London, Britain, December 11, 2015. Picture taken December 11, 2015. (Photo by Neil Hall/Reuters)

The Buddha Dordenma statue overlooks the town of Thimphu, Bhutan, April 16, 2016. (Photo by Cathal McNaughton/Reuters)

These tiny piglets were born and raised at Pennywell Farm in Buckfastleigh, England. Micro or miniature pigs grow to just 14 inches long, and weigh only 9 ounces when they are born. At two years old, they are fully grown and weigh between 40-65 pounds and are around knee height at 12-16 inches tall. Micro pigs can live for up to 18 years, and make popular pets as they are low maintenance, quiet and surprisingly clean. (Photo by Richard Austin/AP Photo/Rex Features)

A close up of a caracal lynx's face looking into a camera on January 2014 in Western Cape, South Africa. (Photo by Dale Morris/Barcroft Media)