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)

Belgium supporters pose before the World Cup quarterfinal soccer match between Argentina and Belgium at the Estadio Nacional in Brasilia, Brazil, Saturday, July 5, 2014. (Photo by Victor R. Caivano/AP Photo)

A mine detection rat is given banana as a reward after successfully identifying an inactive mine on July 2, 2015 in Siem Reap, Cambodia. The Cambodian Mine Action Center (CMAC) working with the Belgian NGO APOPO has recently begun testing the feasability of using large mine detection rats from Tanzania to help clear fields of mines and unexploded ordnance in one of the most bombed and mined countries in the world. (Photo by Taylor Weidman/Getty Images)

People make their way on an algae-covered beach in Qingdao, Shandong province, China, July 19, 2015. (Photo by Reuters/Stringer)

A boy looks inside the skull of a Tyrannosaurus Rex replica at the Egidio Feruglio Museum in Trelew, Argentina, in this May 18, 2014 file photograph. Scientists on July 28, 2015 unveiled a comprehensive analysis of the teeth of the group of carnivorous dinosaurs called theropods, which include the Tyrannosaurus Rex, detailing a unique serrated structure that let them chomp efficiently through the flesh and bones of large prey. (Photo by Maxi Jonas/Reuters)

A man rides a horse at a playground on a hill in Kabul April 19, 2015. (Photo by Mohammad Ismail/Reuters)

An Afghan policeman frisks a man while a burqa-cald woman sits in the trunk of a car on a roadside in Herat, Afghanistan, 05 July 2015. At least 18 police, two civilians and 30 rebels were killed in central Afghanistan during three days of fierce fighting, police said on 04 July. The clashes ended 04 July after security forces retook control of nine police checkpoints that had fallen to the rebels. (Photo by Jalil Rezayee/EPA)

America in the 1970s: Texas. Motorcyclist loading his possessions onto a truck with the help of his friends in Leakey, May 1973. (Photo by Marc St. Gil/NARA via The Atlantic)