A riot policeman watches as a police vehicle burns in Braamfontein, Johannesburg, South Africa, Tuesday, October 25, 2016. Rioters in South Africa set a police vehicle on fire Tuesday and stoned vehicles near a Johannesburg university that has been the scene of sometimes violent protests by students demanding free education. The violence broke out in streets near the University of the Witwatersrand at around the same time that student protesters met and marched off the campus, South African media reported. (Photo by Yeshiel Panchia/AP Photo)

In this October 21, 2015, file photo, a young man rides a hoverboard along a Manhattan street toward the Empire State Building in New York. More than 500,000 hoverboards are being recalled after reports that they can burst into flames. The Consumer Product Safety Commission said Wednesday, July 6, 2016, it has received 99 reports of battery packs in the two-wheel motorized scooters catching fire or exploding that causing burns or property damage. The recalled hoverboards were made by eight companies. (Photo by Kathy Willens/AP Photo)

In this photo taken on Saturday, March 9, 2019, a visitor dances in front of a sculpture burning at the Maslenitsa (Shrovetide) festival at the Nikola-Lenivets art park in Nikola-Lenivets village, about 200 kilometers (125 miles) south-west of Moscow, Russia. As part of the celebrations of Maslenitsa (Shrovetide) Holiday in Russian, a folk holiday which heralds the beginning of spring, contemporary artist and park founder Nikolay Polissky built a giant sculpture made of wood and hay which was burnt to ashes during a traditional bonfire. (Photo by Alexander Zemlianichenko Jr./AP Photo)

A moto-taxi driver takes two passengers past a burning barricade set up by people protesting fuel shortages in Port-au-Prince, Haiti, Monday, September 16, 2019. Haiti was at a standstill Monday with no public transportation available and closed banks, government offices, and schools amid street protests due to a fuel crisis. (Photo by Dieu Nalio Chery/AP Photo)

A masked Burundian protester faces soldiers in front of a burning barricade during an anti-government demonstration against President Pierre Nkurunziza's bid for a third term in the capital Bujumbura, Burundi, 25 May 2015. Street protests continued on 25 May as the United Nations Secretary-General Ban Ki-moon condemned the killing of the leader of the oppsition party Union for Peace and Development (UPD) Zedi Feruzi who opposed Nkurunziza's bid. (Photo by Dai Kurokawa/EPA)

Farmers use tractors and burn tires, hay and manure as they block the highway between Morlaix and Brest during a demonstration against the market prices of their product, on July 22, 2015 in Morlaix, western of France. French farmers protesting over falling food prices threatened to step up blockades of cities, roads and tourist sites, as the government prepared to unveil emergency aid for them. Farmers have dumped manure in cities, blocked access roads and motorways and hindered tourists from reaching Mont St-Michel in northern France, one of France's most visited sites. (Photo by Fred Tanneau/AFP Photo)

A protester throws a stone towards a burning police bus in front of him, during clashes with police, in central Kiev, Ukraine, Sunday, January 19, 2014. Hundreds of protesters on Sunday clashed with riot police in the center of the Ukrainian capital, after the passage of harsh anti-protest legislation last week seen as part of attempts to quash anti-government demonstrations. The violent scenes further escalated this ex-Soviet republic's political crisis and showed a rift among opposition leaders, one of whom fought bravely to stop the violence, while others condemned the events from afar. (Photo by Evgeny Feldman/AP Photo)

Tourists take a “selfie” as demonstrators burn a trash container during a May Day rally in Barcelona, Spain, on May 1, 2014. Tens of thousands of workers marked May Day in European cities with a mix of anger and gloom over austerity measures imposed by leaders trying to contain the eurozone's intractable debt crisis. (Photo by Manu Fernandez/Associated Press)