A man sledges on Primrose Hill with his daughter and their dog on February 5, 2012 in London, England. The United Kingdom is experiencing heavy snowfall with many areas affected. (Photo by Peter Macdiarmid/Getty Images)

Britain Soccer Football, West Ham United vs Manchester United, Barclays Premier League, Old Trafford on May 10, 2016. Police play football with a young West Ham fan before the match. (Photo by Eddie Keogh/Reuters/Livepic)

Egyptian riot police charge towards protesters near Egypt's Interior Ministry, as violent demonstrations continued into their second day on February 3, 2012 in central Cairo, Egypt. (Photo by Ed Giles/Getty Images)

A member of a female grappling team from Qinghai Province armed police undergoes dagger exercise on August 8, 2006 in Xining of Qinghai Province, China. The female grappling team, established in May 2006, has 40 women soldiers aged 18 to 21. The training program includes grappling, boxing, dagger exercise and shooting. (Photo by China Photos). P.S. All pictures are presented in high resolution.

A woman shouts asking for help during an eviction in Rio de Janeiro, Brazil, Friday, April 11, 2014. Squatters in Rio de Janeiro are clashing with police after a Brazilian court ordered that 5,000 people be evicted from abandoned buildings of a telecommunications company. Officers have used tear gas and stun grenades to try to disperse the families. (Photo by Silvia Izquierdo/AP Photo)

People perform during celebrations to commemorate the 70th anniversary of the establishment of the Vietnam Public Security police force at the National Convention Center in Hanoi August 18, 2015. The Vietnam Police force was founded on August 19, 1945, the day of the anti-colonial people's uprising known as the August Revolution. (Photo by Reuters/Kham)

Troops of the Interior Ministry take part in a parade during a ceremony marking the Iraqi Police Day at a police academy in Baghdad January 9, 2016. (Photo by Khalid al Mousily/Reuters)

An injured supporter of Kenyan opposition leader Raila Odinga receives assistance in Nairobi, Kenya on November 17, 2017. Kenyan police have used tear gas and water cannons to disperse supporters of opposition leader Raila Odinga who are trying to gather near the country's main airport and Uhuru park to welcome him back from an overseas trip. (Photo by Baz Ratner/Reuters)