An undercover police officer, who had been marching with anti-police demonstrators, aims his gun at protesters after some in the crowd attacked him and his partner in Oakland, California December 10, 2014. Police said more than 100 demonstrators marched in Berkeley, California, which has a history of social activism. Under cloudy skies, turnout was smaller than earlier in the week, when demonstrators in the area threw rocks at police and shut down a major freeway. (Photo by Noah Berger/Reuters)

Workers collect fish inside an abandoned department store in Bangkok, Thailand January 13, 2015. Staff from Bangkok Metropolitan Administration (BMA) office were catching fish on Tuesday at the ground floor of the roofless New World department store that was closed down in 1997. Thousands of fish such as catfishes, fancy carps as well as black and red tilapias were released into the ground floor of the building, flooded with rainwater, as local vendors tried to control mosquitoes in the area, local media reported. BMA recently decided to remove the fish and release the water. (Photo by Chaiwat Subprasom/Reuters)

A macro view of an ant taking a sip from a water droplet on the edge of a flower in Obihiro, Japan. Animal-Lover Miki Asai has gone a step beyond feeding bread to the ducks – by syringe-feeding water to tiny ants. The office worker from Obihiro City, Japan, squirts droplets near the tiny insects and then uses a macro lens to capture quenching their thirst. The amateur photographer started capturing these images near her house in July 2013 after spotting an ant struggling in the rain. (Photo by Miki Asai/Barcroft Media)

A tourist catches snowflakes on her tongue during snow fall in Times Square, Midtown, New York, on January 3, 2013. A major snowstorm producing blizzard-like conditions hammered the northeastern United States on Friday, causing more than 1,000 U.S. flight delays and cancellations, paralyzing road travel, and closing schools and government offices. (Photo by Darren Ornitz/Reuters)

Vietnamese female traffic police officers march during a rehearsal for a military parade as part of the 40th anniversary of the fall of Saigon in southern Ho Chi Minh City (formerly Saigon City), Vietnam, on April 26, 2015. Vietnam marks the 40th anniversary of the fall of Saigon on April 30, the event that ended a war that lasted over 30 years, killing up to four million Vietnamese, the Vietnamese government said, and more than 58,000 U.S troops, the U.S. Department of Defense has said. (Photo by Reuters/Kham)

A municipal police officer throws a stone back at protesting residents of Kampung Pulo after clashes erupted during an eviction in Jakarta, Indonesia, August 20, 2015 in this photo taken by Antara Foto. Residents facing eviction from a flood-prone part of Indonesia's capital of Jakarta clashed with police on Thursday, prompting security forces to fire tear gas and water cannon. (Photo by Muhammad Adimaja/Reuters/Antara Foto)

Belgian riot police officers are covered by hay and eggs thrown by demonstrators as farmers and dairy farmers from all over Europe take part in a demonstration outside an European Union farm ministers emergency meeting at the EU Council headquarters in Brussels, Belgium, September 7, 2015. Thousands of farmers gathered in the European capital calling for more help with low prices and high costs. (Photo by Jacky Naegelen/Reuters)

A Police officer checks a man wearing a carnival costume in Venice, Italy, Sunday, January 31, 2016. Carnival-goers in Venice are being asked by police to momentarily lift their masks as part of new anti-terrorism measures for the annual festivities. Police are also examining backpacks and bags and using metal-detecting wands before revelers are allowed into St. Mark's Square, the heart of the Venetian carnival. (Photo by Luigi Costantini/AP Photo)