Participants costumed as zombies try to catch hobby runners during the so-called Zombie-Run at the harness racing track Karlshorst in Berlin, Germany, 18 May 2014. The runners carry small flags in their belts which they have to get safely across the finishing line while the zombies try to steal them. The sporting event is based on the US television series “The Walking Dead”. (Photo by Soeren Stache/DPA)

A Sri Lankan activist, who wrapped himself with fire crackers, walks in Colombo on July 23, 2014 to symbolically demonstrate against people burned during Anti-Tamil riots on the island thirty-one years ago. Official accounts placed the death toll at 400 while human rights activists put the toll at thousands. (Photo by Ishara S.Kodikara/AFP Photo)

The anthropomorphic robot named hitchBOT sits on the shoulder of Highway 102 to begin its 6000 kilometer cross country journey outside of Halifax, Nova Scotia, July 27, 2014. The hitch hiking robot is part of a social experiment to see if drivers will pick up and drop off the robot in one piece to an art gallery in Victoria, British Columbia. (Photo by Paul Darrow/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)

Indian labourers carry clay bricks to a brick kiln in Farakka, in the Indian state of West Bengal, on April 3, 2019. (Photo by Xavier Galiana/AFP Photo)

Members of the Bolivarian National Guard who joined Venezuelan opposition leader and self-proclaimed acting president Juan Guaido fire into the air to repel forces loyal to President Nicolas Maduro who arrived to disperse a demonstration near La Carlota military base in Caracas on April 30, 2019. Guaido – accused by the government of attempting a coup Tuesday – said there was “no turning back” in his attempt to oust President Nicolas Maduro from power. (Photo by Federico Parra/AFP Photo)

Fans gather to watch a FIFA World Cup Russia 2018 football match between Brazil and Costa Rica on a giant screen at Alzirao neighborhood in Rio de Janeiro, Brazil on June 22, 2018. (Photo by Carl De Souza/AFP Photo)

Two women jump from a platform over the water at La Concha beach during a hot summer day in the basque city of San Sebastian, northern Spain, Friday, August 3, 2018. Hot air from Africa is bringing a heat wave to Europe, prompting health warnings about Sahara Desert dust and exceptionally high temperatures that could peak at 47 degrees Celsius (117 Fahrenheit) in Spain and Portugal. (Photo by Alvaro Barrientos/AP Photo)