A soldier helps another with her ear protection at the Terningmoen Camp in Elverum, Norway on March 23, 2017. Soldiers demonstrate their skills and tactics during a contract drill as they train to become part of the world's first all-female special forces unit, the Jegertroppen or “hunter troops”. (Photo by Carolina Reid/NBC News)

An employee controls the arms of a manned biped walking robot “METHOD-2” during a demonstration in Gunpo, South Korea, December 27, 2016. It stands 13-feet (3,96 m) tall, weighs 1.3 tons and wields a pair of 286-pound (129,73 kg), motion-tracking metal arms. (Photo by Kim Hong-Ji/Reuters)

Pope Francis waves as he arrives at the Kangemi slums on the outskirts of Kenya's capital Nairobi, November 27, 2015. (Photo by Goran Tomasevic/Reuters)

Two brides kiss during their wedding ceremony to each other at the wedding registry office in St. Petersburg November 7, 2014. The two St. Petersburg women married in the official city ceremony last week, seemingly circumventing Russia's ban on same-s*x marriages. One of the brides was born a man but is undergoing hormone therapy and considers herself a woman. Though her male passport identity ensured the marriage was legal by Russian law, a St. Petersburg lawmaker has vowed to nullify their wedding. (Photo by Reuters/Stringer)

Koreans spin fire cans during “Jwibulnoli” a South Korean folk game at Han River on February 5, 2012 in Seoul, South Korea. The event is part of a “Daeboreum”, a Korean holiday that celebrates the first full moon of the lunar new year. (Photo by Chung Sung-Jun/Getty Images)

A woman at Foyles bookshop looks at a copy of J. K. Rowling's latest novel “The Casual Vacancy” which has gone on sale today starting at 8:00 am on September 27, 2012 in London, England. “The Casual Vacancy” is J. K. Rowling's first book aimed at an adult readership and is centered on a parish council election in a small West Country town. (Photo by Oli Scarf)

Chinese security stands near a Long March 2F rocket carrying Tiangong-1, China's first unmanned space module, stands at the Jiuquan Satellite Launch Center on September 28, 2011 in Jiuquan, Gansu Province of China. Tiangong-1,a small unmanned space lab, will be launched at 21:19 (Beijing time) on September 29, 2011, and will attempt a docking procedure with a Shenzhou 8 spacecraft later in the mission. (Photo by Lintao Zhang/Getty Images)

A view of the screen of a ZaZZZ vending machine that contains cannabis flower, hemp-oil energy drinks, and other merchandise at Seattle Caregivers, a medical marijuana dispensary, in Seattle, Washington February 3, 2015. Vending machines selling medical marijuana opened for business in Seattle on Tuesday, in what the company providing them billed as a first-in-the-state innovation that it expects to expand to other cities and states where pot is legal as medicine. (Photo by David Ryder/Reuters)