An anti-government protester sits on the ground in front of police during a demonstration in Sarajevo February 6, 2014. Hundreds of people turned out in solidarity in the capital Sarajevo, with teenagers throwing eggs and stones at a government building and fought with police. Four officers were taken to hospital, officials said. (Photo by Dado Ruvic/Reuters)

Civilians are led by members of pro-Russian self-defence units as they run outside a military base during an assault in the Crimean town of Belbek near Sevastopol March 22, 2014. Russian troops forced their way into a Ukrainian airbase in Crimea with armored vehicles, automatic fire and stun grenades on Saturday, injuring a Ukrainian serviceman and detaining the base's commander for talks. (Photo by Vasily Fedosenko/Reuters)

King Abdullah of Jordan and Queen Rania who holds Princess Salma in her arms, pose for a portrait November 20, 2000 in Amman, Jordan

An Israeli girl in costume, celebrates the Jewish festival of Purim on March 5, 2004, in Tel Aviv, Israel. The Festival commemorates the rescue of Jews from genocide in ancient Persia.

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)

Megan McKenna, Amber Turner and Yazmin Oukhellou sightings at Aristocats nightclub Mayfair on March 30, 2017 in London, England. (Photo by Goff Photos)

In this April 20, 2017 photo, a woman is aided by fellow demonstrators after falling, overcome by tear gas, during anti-government protests in Caracas, Venezuela. Tens of thousands of protesters asking for the resignation of President Nicolas Maduro flooded the streets again, one day after three people were killed and hundreds arrested in the biggest anti-government demonstrations in years. (Photo by Ariana Cubillos/AP Photo)

A golden huddle by Minqiang Lu, China. Two females and a male golden snub-nosed monkey huddle together to keep warm in the extreme cold. Threatened by forest loss and fragmentation, this endangered species is confined to central China. Restricted to living high up in the temperate forests, these monkeys – here in the Qinling mountains in Shaanxi province – feed mostly in the trees, on leaves, bark, buds and lichen. In heavy wind and snow, Minqiang walked up the mountain carrying his equipment. He stayed for half an hour in temperatures of –10C opposite the tree where the group was huddled before achieving this eye-level composition. (Photo by Minqiang Lu/Wildlife Photographer of the Year)