Military vehicles surround a wreckage of a trolleybus, in Volgograd, Russia, Monday, December 30, 2013. A bomb blast tore through a trolleybus in the city of Volgograd on Monday morning, killing at least 10 people a day after a suicide bombing that killed at least 17 at the city's main railway station. Volgograd is about 650 kilometers (400 miles) northeast of Sochi, where the Olympics are to be held. (Photo by Denis Tyrin/AP Photo)

A prisoner from the Pedrinhas prison is carried to receive medical help after he was injured during a fight between rival gangs inside the jail, in Sao Luiz, capital of Maranhao state, January 8, 2014. The recent posting on a major Brazilian news website of a video filmed last December 17 by Pedrinhas prisoners of the decapitated and tortured bodies of rival inmates inside the jail has highlighted some of the problems present in the country's prison system which houses nearly twice as many prisoners as its capacity, according to official statistics. (Photo by Douglas Cunha/Reuters/O Estado do Maranhão)

A pro-democracy demonstrator fights with a Soviet soldier on top of a tank parked in front of the Russian Federation building on August 19, 1991, after a coup toppled Soviet President Mikhail Gorbachev. The same day, thousands in Moscow, Leningrad, and other cities answered Russian Republic President Boris Yeltsin's call to raise barricades against tanks and troops. (Dima Tanin/AFP/Getty Images)

A grey-bellied Night Monkey (Aotus Lemurinus) plays with a teddy bear at the veterinary clinic of the Cali Zoo in Cali, Colombia on January 27, 2020. They monkey is being raised by personnel of the Cali Zoo after a worker found it near the complex. Apparently it fall from a tree with his father who had health problems. (Photo by Luis Robayo/AFP Photo)

Miss Universe Zozibini Tunzi (C) waves at fans as she is driven through the streets of Johannesburg during her homecoming parade after being crowned in December 2019, Johannesburg, South Africa, 13 February 2020. Zozibini is the first black women to win the title. Miss Universe is an annual international beauty pageant that is run by the United States-based Miss Universe Organization. (Photo by Kim Ludbrook/EPA/EFE)

A Muslim worshipper attends a mass prayer against COVID-19, the new coronavirus, in Dakar on March 4, 2020, after two cases were confirmed in Senegal in the previous days. Across the world, 3,155 people have died from the virus. More than 92,723 have been infected in 78 countries and territories, according to AFP's latest toll based on official sources at 1700 GMT on March 3, 2020. (Photo by John Wessels/AFP Photo)

A masked tourist poses for a souvenir photo next to a graffiti titled “Mobile World Virus” depicting “La Gioconda”, aka Mona Lisa, with a mobile phone and a medical mask, by urban artist TVBoy, close to the Sant Jaume square in Barcelona, Spain, 09 March 2020. Barcelona's Deputy Mayor and two town councillors are in quarantine after they were in contact with a City Hall's worker who was tested positive for the COVID-19 coronavirus. (Photo by Quique Garcia/EPA/EFE)

A woman raises her fist during events to mark Juneteenth, which commemorates the end of slavery in Texas, two years after the 1863 Emancipation Proclamation freed slaves elsewhere in the United States, amid nationwide protests against racial inequality, in the Harlem neighbourhood of Manhattan, in New York City, New York, June 19, 2020. (Photo by Andrew Kelly/Reuters)