A view of the spectacular colour of clouds at sunset on January 17, 2005 in Beijing, China. (Photo by China Photos/Getty Images)

(L-R) Daniel Radcliffe, Emma Watson, J K Rowling and Rupert Grint attend the World Premiere of “Harry Potter And The Deathly Hallows: Part 1” held at The Odeon Leicester Square on November 11, 2010 in London, England. (Photo by Dave Hogan/Getty Images)

Blanka Vlasic of Croatia and Team Europe celebrates a clearance in the women's high jump during the IAAF/VTB Continental Cup at the Stadion Poljud on September 5, 2010 in Split, Croatia. (Photo by Michael Steele/Getty Images)

Catherine, Duchess of Cambridge speaks to soldiers as she arrives at Calgary Airport on July 7, 2011 in Calgary, Canada. (Photo by Chris Jackson/Getty Images)

Four-month-old fox cubs squaring up to each other in Walthamstow, England on August 7, 2015. (Photo by Greg Morgan/Barcroft Media)

A visitor poses for a photograph in front of a 3D painting depicting a Japanese Imperial army soldier at a 3D art gallery in Beijing January 16, 2015. (Photo by Kim Kyung-Hoon/Reuters)

This Thursday, January 22, 2015 photo made with a long exposure shows the glow from a Noctiluca scintillans algal bloom along the seashore in Hong Kong. The luminescence, also called Sea Sparkle, is triggered by farm pollution that can be devastating to marine life and local fisheries, according to University of Georgia oceanographer Samantha Joye. Noctiluca itself does not produce neurotoxins like other similar organisms do. But its role as both prey and predator tends can eventually magnify the accumulation of toxins in the food chain, according to R. Eugene Turner at Louisiana State University. (Photo by Kin Cheung/AP Photo)

Chinese aids activists hand out condoms in a subway train in Wuhan, central China's Hubei province on December 1, 2014. The World Health Organization issued a call to action to China on December 1, 2014 over HIV/AIDS as government figures said nearly half a million people are living with the disease or its precursor, with hundreds of thousands more thought to be undiagnosed. (Photo by AFP Photo)