A rat being trained by the Cambodian Mine Action Centre (CMAC) is pictured on an inactive landmine field in Siem Reap province July 9, 2015. Gambian pouched rats were deployed to Cambodia from Tanzania in April by a Belgian non-profit organization, APOPO, to help clear mines. They've been trained since they were 4 weeks old. Cambodia is still littered with landmines after emerging from decades of civil war, including the 1970s Khmer Rough “Killing Fields” genocide, leaving it with one of the world's highest disability rates. APOPO has used the rodents for mine-clearing projects in several countries, including Angola, Mozambique, Thailand, Laos, and Vietnam. (Photo by Samrang Pring/Reuters)

Migrants rush as they try to get on a train heading to the border with Serbia at the train station of Gevgelija, on the Macedonian-Greek border, on August 9, 2015. Non-EU Serbia's frontier with Hungary, which is in the bloc's passport-free Schengen zone, has become a major crossing point for the huge numbers of migrants entering the EU. (Photo by Dimitar Dilkoff/AFP Photo)

David Pena poses for a photograph with his Lada 2101 built in 1979 on a street in Havana February 9, 2015. Getting parts from the United States is cheaper than in Cuba, where state-run stores sell them at four times the cost, said Pena, a mechanic and president of the Russian Car Club in Havana who drives a souped-up, sporty red 1972 Lada 2101 that he fixed himself. His own Lada has a Fiat engine and an extra Alfa Romeo carburetor. (Photo by Enrique De La Osa/Reuters)

Passengers hold 500 (bottom) rupee banknotes to buy train tickets at a railway booking counter in Allahabad, India, November 9, 2016. People are queuing up outside banks across India to exchange 500 and 1,000 rupee notes after they were withdrawn as part of anti-corruption measures. Indians will be able to exchange their old notes, which stopped being legal tender at midnight on Tuesday, for new ones at banks until 30 December. The surprise move is part of a government crackdown on corruption and illegal cash holdings. Banks were shut on Wednesday to allow them enough time to stock new notes. There are also limits on cash withdrawals from ATMs. The BBC's Yogita Limaye in Mumbai says there have been chaotic scenes outside many banks. (Photo by Danish Siddiqui/Reuters)

A body laying in the street is covered as police block the area around the site of a shooting in Halle an der Saale, eastern Germany, on October 9, 2019. At least two people were killed in a shooting on a street in the German city of Halle, police said, adding that the perpetrators were on the run. “Early indications show that two people were killed in Halle. Several shots were fired. The suspected perpetrators fled in a car”, said police on Twitter, urging residents in the area to stay indoors. (Photo by Sebastian Willnow/dpa/AFP Photo)

Specialist Dilip Patel, left, works at his post on the floor of the New York Stock Exchange, Monday, March 9, 2020. The Dow Jones Industrial Average sank 7.8%, its steepest drop since the financial crisis of 2008, as a free-fall in oil prices and worsening fears of fallout from the spreading coronavirus outbreak seize markets. (Photo by Richard Drew/AP Photo)

A 9 year old girl receives digital lessons from the primary school teacher in Rotterdam, Netherlands on April 20, 2020, because the schools are closed due to the corona crisis staying at home. Many schools are putting together a homework package or using digital teaching methods, now that education has been closed for several weeks due to the corona virus. (Photo byRobin Utrecht/Rex Features/Shutterstock)

Summer Zhai and Vicky He, dressed as characters from the anime "Love Live!", rest on stairs during day two of New York Comic Con in Manhattan, New York, October 9, 2015. The event draws thousands of costumed fans, panels of pop culture luminaries and features a sprawling floor of vendors in a space equivalent to more than three football fields at the Jacob Javitz Convention Center on Manhattan's West side. (Photo by Andrew Kelly/Reuters)