An artist's impression of a growing supermassive black hole located in the early Universe is seen in this NASA handout illustration released on June 15, 2011. Using the deepest X-ray image ever taken, astronomers found the first direct evidence that massive black holes were common in the early universe. This discovery from NASA's Chandra X-Ray Observatory shows that very young black holes grew more aggressively than previously thought, in tandem with the growth of their host galaxies. (Photo by Reuters/NASA/Chandra X-Ray Observatory/A.Hobart)

The International Garden Photographer of the Year is one of the world’s premier competitions specialising in botanical photography. There are 11 main categories and numerous special awards including Young Garden Photographer of the Year, and the mobile-only category Gardens on the Go. Here: Winner, Wildflower Landscapes category. Alto Paraíso de Goiás, Goiás, Brazil. (Photo by Marcio Cabral/The Guardian)

British soldiers inspect a captured German place in the Horseguards' Parade, London during World War I in November 1914, with the London Eye in the background as a reminder of just how much has changed in the last 100 years. (Photo by Peter Macdiarmid/Getty Images)

Machu Picchu, Peru. A llama’s-eye view of the legendary Inca settlement at Machu Picchu, isolated high in the Peruvian Andes. (Photo by Jim Turner/National Geographic)

Night lovers; Hormozgan province, Iran. “In this picture, you can see the Milky Way rising on a fascinating spring night on the Persian Gulf coast. The stunning cliffs of this area make every viewer imagine and even talk to them! The light pollution from a faraway city was quite strong, so it was a challenging post-processing process. I’m a nightscaper who tries to achieve an artistic look in my images, and in this image, I tried to convey and capture the magic of this location”. (Photo by Mohammad Hayati/Milky Way Photographer of the Year)

Aurora Australis from Beerbarrel Beach, by James Stone. Runner Up: Aurorae. (Photo by James Stone/Astronomy Photographer of the Year)

Hemispheric color differences on Saturn's moon Rhea are apparent in this false-color view from NASA's Cassini spacecraft in this March 2, 2010 file photo. (Photo by Reuters/NASA/JPL/SSI)

Two women look at a mobile phone as they stand on Tiananmen Square during a sand storm in heavily polluted weather in Beijing on February 28, 2013. Beijing residents were urged to stay indoors as pollution levels soared before a sandstorm brought further misery to China's capital. (Photo by Ed Jones/AFP Photo)