Saudi youths demonstrate a stunt known as “sidewall skiing” (driving on two wheels) in the northern city of Tabuk, in Saudi Arabia December 3, 2014. (Photo by Mohamed Al Hwaity/Reuters)

Members of the U.S. Army 173rd Airborne Brigade stand at attention as a Ukrainian folk dance group performs at the opening ceremony of the “Rapid Trident” NATO military exercises on September 15, 2014 near Yavorov, Ukraine. The two-week exercises include participating units from a variety of NATO and NATO-associate countries as well as Ukrainian troops. Meanwhile fighting between pro-Russian separatists and Ukrainian armed foces has flared again in eastern Ukraine in a battle for the control of Donetsk airport despite the tenuous ceasefire. (Photo by Sean Gallup/Getty Images)

Wedges of an orange generate enough current and electrical juice – 3.5 volts – to power an LED. The fruit’s citric acid helps electrons flow from galvanized nails to copper wire in this 14-hour exposure. This image was published in September’s Visions of Earth, a trio of photos that appear in each issue of National Geographic. (Photo by Caleb Charland/National Geographic)

A woman with a sign that reads in Portuguese “Being woman without Temer”, stands next to a police barricade during a protest against the gang rape of a 16-year-old girl in Sao Paulo, Brazil, Wednesday, June 1, 2016. In response to the assault, Brazil's interim President Michel Temer said that the country will set up a specialized group to fight violence against women. (Photo by Andre Penner/AP Photo)