Vietnamese female traffic police officers march during a rehearsal for a military parade as part of the 40th anniversary of the fall of Saigon in southern Ho Chi Minh City (formerly Saigon City), Vietnam, on April 26, 2015. Vietnam marks the 40th anniversary of the fall of Saigon on April 30, the event that ended a war that lasted over 30 years, killing up to four million Vietnamese, the Vietnamese government said, and more than 58,000 U.S troops, the U.S. Department of Defense has said. (Photo by Reuters/Kham)

A protester jumps on the table in front of the European Central Bank President Mario Draghi during a news conference in Frankfurt, Germany April 15, 2015. (Photo by Kai Pfaffenbach/Reuters)

Twin baby panthers Remaong and Ferra cling to their basket while being presented to the media at Tierpark Berlin zoo on July 13, 2012 in Berlin, Germany. The two panthers were born in captivity on April 26. (Photo by Sean Gallup)

An abandoned protection masks in the deserted building near bypass channel for cooling at the Chernobyl nuclear power plant in the Exclusion Zone, Ukraine, April 5, 20177. The Chernobyl nuclear accident occurred on 26 April 1986 in the No.4 light water graphite moderated reactor at the Chernobyl Nuclear Power Plant near Pripyat. An estimated 47,000 people of the city of Pripyat were evacuated after the explosion in 1986. (Photo by Vitaliy Holovin/Corbis via Getty images)

Riot policemen stand in formation during street protests against the decision made by Burundi's ruling National Council for the Defence of Democracy-Forces for the Defence of Democracy (CNDD-FDD) party to allow President Pierre Nkurunziza to run for a third five-year term in office, in the capital Bujumbura, April 26, 2015. Police in the Burundian capital used water cannon and tear gas on Sunday to disperse protesters demonstrating against Nkurunziza seeking a third term, witnesses said, after the government banned protests for or against the move. (Photo by Thomas Mukoya/Reuters)

Members of the Jordanian police women's team attend the 7th Annual Warrior Competition at the King Abdullah Special Operations Training Center in Amman April 22, 2015. Thirty-eight teams from 18 countries are participating in the competition to test their military skills. (Photo by Muhammad Hamed/Reuters)

Colombian Jahn Fredy Duque, dressed as superhero “Spiderman”, performs on the streets in Bogota, Colombia on April 24, 2017. Duque hangs a white cloth 26 meters long – his cobweb – from a bridge near the international center of Bogota, where he performs in the street for a livelihood. (Photo by Raul Arboleda/AFP Photo)

People decorate a street with candles inside oranges during the Epitaph ceremony during Good Friday's “Apokathelosis”, the Descent of Christ's dead body from the Cross, which forms a key part of Orthodox Easter, in the southern city of Leonidio, at the Peloponnese peninsula on April 26, 2019. Millions of Greeks flock to churches around the country this week to celebrate Easter, the country's foremost religious celebration. (Photo by Aris Messinis/AFP Photo)