Couples kiss during a kissing contest in Wuhan, Hubei province, November 23, 2014. Some 20 couples attended the contest and the winners have been awarded an iPhone 6, according to local media. (Photo by Reuters/Stringer)

Argentine Juan Manuel Silva and Pablo Sisterna (not pictured) crash in their Mercedes car during the 7th stage of the Dakar Rally from Iquique to Uyuni, January 10, 2015. (Photo by Daniel Rodrigo/Reuters)

Maria Gabriela de Faria arrives at Nickelodeon's 28th annual Kids' Choice Awards at The Forum on Saturday, March 28, 2015, in Inglewood, Calif. (Photo by Chris Pizzello/Invision/AP Photo)

A dead body is seen on the ground after violence erupted in the Independence Square in Kiev February 20, 2014. Ukrainian protesters seized back Kiev's Independence Square in fresh clashes with riot police on Thursday that left several injured and possibly two demonstrators dead. (Photo by David Mdzinarishvili/Reuters)

Actress Frederique Bel attends the Opening ceremony and the “Grace of Monaco” Premiere during the 67th Annual Cannes Film Festival on May 14, 2014 in Cannes, France. (Photo by Pascal Le Segretain/Getty Images)

A man holds on a rope as he tries to board a truck while crossing floodwaters brought by typhoon Koppu that battered Candaba town, Pampanga province, north of Manila October 20, 2015. Typhoon Koppu swept across the northern Philippines killing at least nine people as trees, power lines and walls were toppled and flood waters spread far from riverbeds, but tens of thousands of people were evacuated in time. (Photo by Romeo Ranoco/Reuters)

Graffiti is painted on the bathroom walls at a restaurant in the Williamsburg area of Brooklyn borough in New York, United States, October 1, 2015. Some 2.4 billion people around the world don't have access to decent sanitation and more than a billion are forced to defecate in the open, risking disease and other dangers, according to the United Nations. To mark World Toilet Day on November 19, Reuters photographers captured pictures of toilets in cities, towns and villages around the globe. (Photo by Shannon Stapleton/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)