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)

New York Police Department tactical police officers stand guard near the New York Stock Exchange on September 9, 2011 in New York City. Officials are stepping up security in New York and Washington D.C. a day after U.S. officials received a credible but unconfirmed terror threat to utilize car bombs on bridges or tunnels in New York or Washington. (Photo by Justin Sullivan/Getty Images)

A fly rides a butterly, July 2016. (Photo by Petar Sabol Sharpeye/Rex Features/Shutterstock)

A model poses beside a Mazda MX-5 during a media presentation at the 37th Bangkok International Motor Show in Bangkok, Thailand, March 22, 2016. (Photo by Chaiwat Subprasom/Reuters)

This restroom on the rubbly flanks of Jonsknuten in Norway looks up at the peak of the 904m mountain. Yu have to leave the door open to enjoy the view but the chances of being disturbed are minimal. (Photo by Olaf Menz/Lonely Planet)

Spectacular images offering insight into the lives of the Huaorani people in the Ecuadorian Amazon have been revealed showing how they use traditional methods to hunt monkeys for food. The stunning pictures were taken by conservation photographer Pete Oxford from Torquay, Devon in the Ecuadorian Amazon. Here: The tribe were seen celebrating after a hunter returned to camp with a wild pig. (Photo by Pete Oxford/Mediadrumworld.com)

Brain-on-a-chip. Dazzling in green and magenta this image shows the nerve fibres (in green) produced by neural stem cells (in magenta) as they grow on a synthetic gel. Captured by a technique known as confocal microscopy, the image is part of research shedding light on how tinkering with the environment can affect the way in which nerve fibres grow. (Photo by Collin Edington and Iris Lee/Massachusetts Institute of Technology/Wellcome Images)

Wildlife photographer Danté Fenolio has headed into areas untouched by sunlight – deep seas, caves and underground – and found creatures that are exploding with colour. Here: The golden harlequin toad has vanished from the wild, and only a small number live on in captivity. A fungus caused them, and many other amphibians, to die out in their home in Central America. (Photo by Danté Fenolio/The Guardian/Johns Hopkins University Press)