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 man feeds monkeys at Longchi scenic area, in Dujiangyan, Sichuan province, China May 24, 2017. (Photo by Reuters/Stringer)

A worker roasts rows of freshly slaughtered pigs, known locally as “lechon” and famously served as main courses during the New Year revelry, at a store in Manila, Philippines, December 31, 2016. (Photo by Ezra Acayan/Reuters)

A commuter exits a closed off station after a subway train derailment, Tuesday, June 27, 2017, in the Harlem neighborhood of New York. A subway train derailed near a station in Harlem on Tuesday, frightening passengers and resulting in a power outage as people were evacuated from trains along the subway line. The Fire Department of New York said a handful of people were treated for minor injuries at around 10 a.m. It said there was smoke but no fire. Delays were reported throughout the subway system. (Photo by Mary Altaffer/AP Photo)

A participant wearing a costume poses for members of the public before the 40th anniversary of the Sydney Gay and Lesbian Mardi Gras Parade in central Sydney, Australia, March 3, 2018. (Photo by David Gray/Reuters)

Ai (R) and Hamuka dressed in “Lolita fashion”, influenced by Victorian style, pose for a photographs at Harajuku shopping district in Tokyo, Japan March 15, 2018. (Photo by Kim Kyung-Hoon/Reuters)

Private Harold L. Langhofer edges into the ball-turret, March 9, 1943. Curled in this position, he can turn the turret so that it fires in any direction. The turret can also be swung around so that the hatch opens into the plane, and the gunner can crawl into it while the Flying Fortress is in motion. (Photo by AP Photo)

A visitor and an employee dressed as Snegurochka (Snow Maiden), the granddaughter of Ded Moroz (Russian equivalent of Santa Claus), pose for a picture inside an upside down house, constructed as an attraction for local residents and tourists and located at the Royev Ruchey Park of Flora and Fauna in the suburbs of Krasnoyarsk, Russia, December 7, 2016. (Photo by Ilya Naymushin/Reuters)