In this Monday, March 18, 2019 photo, a street artist performs in Caracas, Venezuela. Venezuelans are facing a severe economic and political crisis as President Nicolas Maduro has remained in power despite heavy pressure from the United States and other countries arrayed against him, managing to retain the loyalty of most of Venezuela's military leaders. (Photo by Natacha Pisarenko/AP Photo)

A girl with Russian national flags painted on her cheeks takes part in celebrations marking the first anniversary of Russia's annexation of Crimea, in central Simferopol March 16, 2015. Russia marks one year anniversary of annexation of Ukraine's Crimea peninsula this week. (Photo by Maxim Shemetov/Reuters)

This artist's scoreboard displays a fictional game between Mars and Earth, with Mars in the lead. It refers to the success rate of sending missions to Mars, both as orbiters and landers. Of the previous 39 missions targeted for Mars from around the world, 15 have been successes and 24 failures. For baseball fans, that's a batting average of .385. The United States has had 13 successes out of 18 attempts, or a “batting average” of .722. NASA's Curiosity rover, set to land on the Red Planet the evening of Aug. 5, 2012 PDT (morning of Aug. 6 EDT), will mark the United States' 19th attempt to tackle the challenge of Mars, and the world's 40th attempt. (Image by NASA/JPL-Caltech)

A girl plays with coloured chicks for sale prior to Easter celebrations in Byblos, Lebanon on March 22, 2015. (Photo by Jamal Saidi/Reuters)

A dead crocodile is seen on Huangsha Seafood Market in Guangzhou, Guandong Province, China, 22 January 2018. Tsukiji Market of China or Huangsha Seafood Market is biggest one in Southern China and one of the biggest in China, as there are literally hundreds of different varieties of fish and seafood scattered throughout the market. (Photo by Aleksandar Plavevski/EPA/EFE)

A jockey takes part in a traditional cattle race or “Pacu Jawi”, to mark the end of the rice harvest in Tanah Datar, West Sumatra, Indonesia, August 13, 2016 in this photo taken by Antara Foto. (Photo by Hafiz Mubarak A./Reuters/Antara Foto)

A Los Angeles County firefighter puts water a burning house in a wildfire in the Lake View Terrace area of Los Angeles Tuesday, December 5, 2017. Ferocious winds in Southern California have whipped up explosive wildfires, burning a psychiatric hospital and scores of other structures. Tens of thousands of people have been ordered evacuated. (Photo by Chris Carlson/AP Photo)

Two elderly men smoking pipes of opium on a terrace in Korea. (Photo by Bert Hardy/Picture Post/Getty Images). August 1950