A competitor wearing a kilt and standing on a barrel throws a bowling ball between her legs during the “Brigaball” contest at the annual Bundanoon Highland Gathering, showcasing traditional Scottish events, held in the town of Bundanoon, located southwest of Sydney, April 9, 2016. (Photo by David Gray/Reuters)

Children are engulfed by foam during the Bubble Show event in Beijing, China, Sunday, June 26, 2016. Thousands of residents enjoy colored foam churned out by machines along a running track at the event designed for children and parents' interaction. (Photo by Ng Han Guan/AP Photo)

A woman uses a tree branch to fight a fire on the road leading to the village of Parada, near Mortagua, northern Portugal, Thursday, August 11 2016. Firefighters in Portugal are battling multiple blazes fed by brush in a hot, dry summer for a sixth straight day. Major fires have also been raging in northwestern Spain and southern France. (Photo by Sergio Azenha/AP Photo)

“Weapons Instructor”, 2012. It’s a well known fact that the IDF trains some of the best soldiers in the world, but at the source of every good soldier lies an exceptional instructor – and that’s where Cpl. Daniella Stepanoe steps in. She travels from base to base training everyone from paratroopers to elite special forces units in the use of their weapons. (Photo by Israel Defense Forces)

A Hindu holy man is reflected on a mirror as he prepares a bowl of vermillion powder for devotees near “Sangam”, the confluence of holy rivers of Ganges, Yamuna and the mythical Saraswati, during the annual traditional fair of Magh Mela in Allahabad, in the northern Indian state of Uttar Pradesh, India, Tuesday, January 6, 2015. Hundreds of thousands of devout Hindus are expected to take holy dips at the confluence during the astronomically auspicious period of over 45 days celebrated as Magh Mela. (Photo by Rajesh Kumar Singh/AP Photo)

Eighty one-year-old Sakon Haba (L) wearing loin cloth walks past a police station after he bathed in ice-cold water at the Teppozu Inari shrine in Tokyo January 11, 2015. According to organizers, about 100 participants took part in the Shinto ceremony to purify their souls and wish for good health in the new year. (Photo by Toru Hanai/Reuters)

An Afghan journalist takes a “selfie” as U.S. President Barack Obama (R) holds a joint news conference with Afghanistan's President Ashraf Ghani (C) at the White House in Washington March 24, 2015. (Photo by Jonathan Ernst/Reuters)

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)