A Polish Air Force MIG-29 fighter (R) and an Italian Air Force Eurofighter Typhoon fighter patrol over the Baltics during a NATO air policing mission from Zokniai air base near Siauliai, Lithuania February 10, 2015. (Photo by Ints Kalnins/Reuters)

These picture look like an artist has painted abstract patterns on canvas – but in fact they are natural rivers captured on camera. The spectacular rivers in Iceland's central highlands and southern parts originate from glaciers, which is why the water is a milky colour. They are shallow rivers and the water spreads quickly over a flat and sandy surface, creating random and beautiful patterns. Photographer Andrey Ermolaev from Moscow, Russia, flew 500ft above the unique sight in a small plane. (Photo by Andrey Ermolaev/Solent News)

Vladimir Putin shows a hold to a young judo wrestler at the Regional Judo Center at the Arena Sports Complex in the Siberian city of Kemerovo on January 24, 2012, during his visit to the region. Putin is known for his passion for judo, in which he has a black belt. (Photo by AFP Photo/STR)

The First U.S. Spacewalk – Gemini 4 Ed White made the United States' first spacewalk on June 3, 1965 during the Gemini 4 mission. The extra-vehicular activity (EVA) started at 19:45 UT (3:45 p.m. EDT) on the third orbit when White opened his hatch and used the hand-held manuevering oxygen-jet gun to push himself out of the capsule. (Photo by NASA)

This strange coral-looking specimen is actually a mushroom. The photo, “Beautiful Destroyer”, was taken in the Panamanian tropical rainforest where the mushroom produces nitrogen, an element vital to soil health. (Photo by Sarah A. Batterman)

A selection of work by four photojournalists who have won grants of $10,000 and editorial support from the agency. Here: “Chasing Winter” by Katie Orlinksy. In late summer and early autumn polar bears flock to the native village of Kaktovik in the Alaskan Arctic to eat at “the boneyard” – the remains of whales annually hunted by the community. (Photo by Katie Orlinsky/Getty Images)

Artist Pyotr Pavlensky sits on the wall enclosing the Serbsky State Scientific Center for Social and Forensic Psychiatry after he cut off a part of his earlobe during his protest action titled “Segregation” in Moscow October 19, 2014. Pavlensky protested against the usage of forensic psychiatry for politically motivated purposes. He cut off his earlobe to demonstrate how authorities could “cut off” an unwanted individual from society by using psychiatric and medical diagnosis to forcefully send a person to a penitentiary hospital, according to Pavlensky. (Photo by Maxim Zmeyev/Reuters)

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)