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)

Timbuktu: A UN peacekeeper from Burkina Faso stands guard at the Djinguereber mosque, built in the 14th century, during a visit by a UN delegation on election day in Timbuktu, Mali, July 28, 2013. (Photo by Joe Penney/Reuters)

An elephant dressed in a Santa Claus costume gives out gifts to students to mark the Christmas season at a school in Ayutthaya province on December 24, 2010. The event was held as part of a campaign to promote Christmas in Thailand. (Photo by Pornchai Kittiwongsakul/AFP Photo)

The giant metal structure sits 330ft above the ground on the roof of a 22 storey office block in Dutch capital Amsterdam on September 6, 2016. Tourists sit in a playground-style chair as they propel themselves them over the edge of the building with only thin-air between them and the ground below. Engineers spent several years designing and building the breathtaking swing. By being fixed to the top of a building it reaches new heights – dwarfing other swings around Europe but trailing behind the 1,150ft high mechanical rides at the Stratosphere Hotel in Las Vegas, Nevada. (Photo by Huub Zeeman/SWNS.com)

A reflection of the Alps mountain “Nordkette” is seen in the ski googles of Anders Bardal of Norway during the training round of the FIS Ski Jumping World Cup event at the 60th Four Hills ski jumping tournament at Bergisel on January 3, 2012 in Innsbruck, Austria. (Photo by Alexander Hassenstein/Bongarts/Getty Images)

In this September 10, 1977, file photo, from left, Hua Guofeng, Chinese Communist Party (CCP) chairman and Mao Zedong's immediate successor; Ye Jianying, CCP vice chairman and future ceremonial head of state; Deng Xiaoping, no formal titles at the time but soon to emerge as paramount leader during the reform era; Li Xiannian, CCP vice chairman and future president; Wang Dongxing, head of the leadership bodyguard unit who helped topple the Gang of Four, view the body of later Chinese leader Mao Zedong in Beijing. (Photo via AP Photo)

Karima Adebibe, the newly crowned face of Lara Croft, poses, with a Burmese python on the eve of the release of the record breaking new video game “Lara Croft Tomb Raider; Legend” at The Barbican on April 6, 2006 in London, England. (Photo by Gareth Cattermole/Getty Images)