Riot police officers in position to crack down on demonstrators during a protest against Venezuelan President Nicolas Maduro, in Caracas on April 20, 2017. Venezuelan riot police fired tear gas Thursday at groups of protesters seeking to oust President Nicolas Maduro, who have vowed new mass marches after a day of deadly unrest. Police in western Caracas broke up scores of opposition protesters trying to join a larger march, though there was no immediate repeat of Wednesday's violent clashes, which left three people dead. (Photo by Juan Barreto/AFP Photo)

A security man keeps guard during Malawi's President elect Arthur Peter Mutharika swearing in ceremony at Kamuzu Stadium in Blantyre on May 28, 2019, after a contentious election marred by allegations of fraud and vote-rigging. The Malawi Electoral Commission announced on Monday that Mutharika, who heads the ruling Democratic Progressive Party (DPP), had narrowly won last week's vote after an injunction barring the release of the results was lifted. (Photo by Amos Gumulira/AFP Photo)

A string art picture made by artist Ani Abakumova in a workshop in the village of Romashkovo in Moscow Region, Russia on August 2, 2019. Ani Abakumova and her husband Andrei Abakumov create string art replicas of famous paintings. Andrei makes computer calculations that show patterns for future images, then Ani winds coloured strings around nails hammered around a plywood board. (Photo by Anton Novoderezhkin/TASS)

In this photo taken on Thursday, August 22, 2019, and distributed by Roscosmos Space Agency Press Service, the Russian Progress 73 cargo ship blasts off from the launch pad at Russia's space facility in Baikonur, Kazakhstan. The new Russian rocket, that is expected to replace the current model sending manned missions into space, blasted off from Kazakhstan on Thursday, carrying a Soyuz capsule with a humanoid robot. (Photo by Roscosmos Space Agency Press Service via AP Photo)

This photo shows sunset in Eagle, Colo., Sunday, November 3, 2019. Daylight saving time ended, making sunset around 5 p.m. this time of year in Colorado. (Photo by Chris Dillmann/Vail Daily via AP Photo)

A sledding dog is covered in ice after spending the night in the open air with his musher at the polar base of Val-Cenis, as they ready for the next stage of the 12th edition of “La Grande Odyssee” sledding race across the Alps on January 17, 2016 in Val Cenis Lanslevillard. (Photo by Jean-Philippe Ksiazek/AFP Photo)

Ivan Shamyanok, 90, shaves in his house in the village of Tulgovichi, near the exclusion zone around the Chernobyl nuclear reactor, Belarus March 15, 2016. “My sister lived here with her husband. They decided to leave and soon enough they were in the ground ... They died from anxiety. I'm not anxious. I sing a little, take a turn in the yard, take things slowly like this and I live”, he said. (Photo by Vasily Fedosenko/Reuters)

A villager watches as Mount Sinabung volcano erupts, in Kuta Tengah village, Karo Regency in Indonesia's North Sumatra April 1, 2015. The Indonesian volcano was dormant for 400 years before erupting in 2010. (Photo by Y. T. Haryono/Reuters)