A demonstrator catches fire after the gas tank of a police motorbike exploded during clashes in a protest against Venezuelan President Nicolas Maduro, in Caracas on May 3, 2017. Venezuela' s angry opposition rallied Wednesday vowing huge street protests against President Nicolas Maduro' s plan to rewrite the constitution and accusing him of dodging elections to cling to power despite deadly unrest. (Photo by Juan Barreto/AFP Photo)

Two revelers dressed as toy soldiers gesture toward a police officer in a patrol car during the traditional carnival parade in Wuerzburg, Germany, 15 February 2015. Under the motto “Carnival Parade is cool” about 160 groups with over 3,000 members took part in one of the biggest carnival parades in southern Germany. (Photo by Daniel Karmann/EPA)

A riot policeman punches Greek photojournalist Tatiana Bolari during a demonstration in Athens' Syntagma (Constitution) square October 5, 2011. Police officers attacked several members of the press covering protests, injuring at least two members of the media. (Photo by Yannis Behrakis/Reuters)

North Korea has closed its borders in fear of the spread of the Ebola virus. But at a time when the secretive state was still welcoming tourists, former aid worker Andrew Macleod made the journey to the repressive nation. Andrew's holiday snaps and camera footage provide a unique insight into the reclusive country, where he came across deserted motorways, metro stations plastered with propaganda and attractive border guards. Here: a female traffic police officer in the snow in February 2013, in Pyongyang, North Korea. (Photo by Andrew Macleod/Barcroft Media)

Children guarded by Hungarian police play on the ground after being detained along with other migrants who illegally crossed from Serbia to Hungary near the village of Asotthalom, Hungary, September 16, 2015. (Photo by Dado Ruvic/Reuters)

A fellow officer comes to the aid of injured patrolman C.V. Satt, who was pelted with rocks and beer bottles during a clash between police and relief demonstrators in Denver September 23, 1935. (Photo by Henry G. Eisenhand/AP Photo)

Members of the public continue to pay their respects at the scene of a hit and run following civil disturbances in the Winson Green area on August 12, 2011 in Birmingham, England. Police are continuing investigations after three people – reportedly trying to protect shops from rioting and looting in Dudley Road – were struck by a car and killed during rioting. Police have so far arrested over 1,000 people following rioting which erupted over a four-day period across the UK. (Photo by Jeff J Mitchell/Getty Images)

Russian Police detain opposition supporters during a “March of Millions” protest rally against Vladimir Putin's return in Moscow, Russia on May 6, 2012. Over 650 people were arrested including opposition leaders. (Photo by Dmitry Schedrin, Rustem Adagamov, Andrey Stenin)