Artists perform during the opening show directed by German director Volker Hesse, on the opening day of the Gotthard rail tunnel, at the fairground Rynaecht at the northern portal in Erstfeld, Switzerland, Wednesday, June 1, 2016. The construction of the 57 kilometer long tunnel began in 1999, the breakthrough was in 2010. After the official opening on June 1, the commercial operation will start in December 2016. (Photo by Ruben Sprich\Pool Photo via AP Photo)

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 racegoers walks into a rubbish bin following 2016 Melbourne Cup Day at Flemington Racecourse on November 1, 2016 in Melbourne, Australia. (Photo by Scott Barbour/Getty Images)

Japanese macaques are relaxed in an outdoor hot spring bath at Hakodate Tropical Botanical Garden on December 1, 2016 in Hakodate, Hokkaido, Japan. The garden offers the hot spring treatment to macaques until May next year. (Photo by The Asahi Shimbun via Getty Images)

A tank crew competes in an individual race at a regional stage of the 2016 Tank Biathlon Competition at the Anastasyevsky training ground, March 1, 2016, Khabarovsk Territory, Russia. (Photo by Yuri Smityuk/TASS/Newscom)

Wizz Air's Airbus A-321 flying along the Danibe river during an air show in Budapest, Hungary, May 1, 2016. (Photo by Laszlo Balogh/Reuters)

Performers dressed like Stormtroopers dance during “The Empire Strips Back: A Star Wars Burlesque Parody” in Los Angeles, California, U.S., June 1, 2018. (Photo by Mario Anzuoni/Reuters)

A performer dances during “The Empire Strips Back: A Star Wars Burlesque Parody” in Los Angeles, California, U.S., June 1, 2018. (Photo by Mario Anzuoni/Reuters)