Models painted in camouflage colours to blend in with the background pose for Chinese artist Liu Bolin's artwork “Dongji”, or Winter Solstice, on the second day after China's capital Beijing issued its second ever “red alert” for air pollution, in Beijing, China, December 20, 2015. In this artwork, Liu wants to express his concerns about China and its people, including air pollution problem, Liu told Reuters. (Photo by Kim Kyung-Hoon/Reuters)

Neil Zeller's snaps were taken across Canada, where he photographs the northern lights dancing across a dark night sky. In one stunning shot, Zeller, 42, even manages to capture a flash of lightning beneath a storm cell while an aurora gives off a magnificent green glow. The photographer, from Calgary, Alberta, describes himself as a night person, and became interested in night photography about 10 years ago. (Photo by Neil Zeller/Caters News)

Men wearing masks and dressed as military members take part in a festival honouring San Silvestre, in the town of Catarina, Nicaragua January 1, 2016. The placard reads, “I'm not afraid, young people off the streets, Ortega you sell our country”, in reference Nicaragua's President Daniel Ortega. (Photo by Oswaldo Rivas/Reuters)

A woman attends a boxing class at Princess Women's Boxing Club in Shanghai December 3, 2014. Women have boxed as long as the sport has existed but for years they were relegated out of national and international competitions in many countries around the world. Female boxers entered the ring in an exhibition match at the 1904 Olympic Games, but it was more than a century later when they were given the green light to make their Olympic debut in London in 2012. (Photo by Carlos Barria/Reuters)

Members of the Bolivian combined forces of army and police rest at their headquarters at the end of their ceremony for the task of fighting against drugs and the eradication of coca leaves in Chimore, east of La Paz, December 10, 2014. The government of Bolivia's President Evo Morales eradicated some 11,000 hectares of illegal coca plants and confiscated nearly 192 tons of drugs in 2014, according to the local media. (Photo by David Mercado/Reuters)

A women attends a class at a driving school in Kabul August 17, 2014. Kabul is one of the world's fastest growing cities and its streets are increasingly blocked by cars and buses. In the city's private driving schools, students pay a $60 fee for a 45-day course, which includes oral and practical driving tests at the country's Traffic Department. Some of the women who have signed up say learning to drive is a way to escape unwanted gazes and physical harassment on the cramped, crowded minibuses that are often the only method of urban public transport. (Photo by Mohammad Ismail/Reuters)

A bride from the Santa Marta slum takes a break after getting her makeup done before a group wedding in Rio de Janeiro December 17, 2014. A total of 16 couples took part in a mass wedding ceremony organized by the Police Peacekeeping Unit (UPP) as part of activities geared towards social enhancement of the slums. (Photo by Pilar Olivares/Reuters)

Personal possessions of 2004 tsunami victims are arranged to be photographed outside a police station in Takua Pa, in Phang Nga province December 19, 2014. Thai police opened a shipping container filled with documents and possessions of victims of the 2004 Indian Ocean Tsunami after being asked by Reuters for permission to film its contents. The three metre by 12 metre container was handed over to Thai police in 2011 and contains hundreds of plastic police evidence bags – each one holding the precious items found on the body of a victim. (Photo by Damir Sagolj/Reuters)