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)

Visitors and a dog stand on the new “Skywalk” viewing platform on the Sonnenstein mountain in the Eichsfeld region near Bad Lauterberg im Harz, central Germany, on May 22, 2017. (Photo by Martin Schutt/AFP Photo/DPA)

Russians play accordions as they walk near the building of the Federal Security Service (FSB, Soviet KGB successor) in Lubyanskaya Square to mark May Day in Moscow, Russia, Sunday, May 1, 2016. As in Soviet times, about one hundred thousand of cheerful workers paraded across Red Square despite a chilly rain, but instead of red flags with the Communist hammer and sickle, they waved the blue flags of the dominant Kremlin party and the Russian tricolor. (Photo by Alexander Zemlianichenko/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)

Forensic investigators look at the body of a man infected with the new coronavirus who collapsed on the street and died, according to Police Captain Diego Lopez, in Quito, Ecuador, Tuesday, May 5, 2020. (Photo by Dolores Ochoa/AP Photo)

Russian Boxing Federation lifts a portrait of late Soviet leader Joseph Stalin with a hot air balloon, close to city of Belogorsk outside Simferopol, Crimea, on May 11, 2020, to mark the 75th anniversary of the end of World War II also called the Great Patriotic War, amid the coronavirus (COVID) pandemic. (Photo by AFP Photo/Stringer)

A serviceman of Russia's Emergencies Ministry wearing protective gear disinfects Moscow's Leningradsky railway station on May 19, 2020, amid the COVID-19 coronavirus pandemic. (Photo by Kirill Kudryavtsev/AFP Photo)

A woman holds her inhaler and leans on another person after being sprayed with mace by police officers during a protest near the Minneapolis Police third precinct after a white police officer was caught on a bystander's video pressing his knee into the neck of African-American man George Floyd, who later died at a hospital, in Minneapolis, Minnesota, U.S. May 27, 2020. (Photo by Eric Miller/Reuters)