Aeronautics and Space engineer at France's Compagnie Maritime d'Expertises, or Comex, Arnaud Prost (C) meets with a jogger as he tests on the ground the “Gandolfi 2” underwater training suit for spacewalk, on January 20, 2016 in the calanques region (rocky inlets) of Marseille. The underwater training suit “Gandolfi 2”, developed with the European Space Agency (ESA), is designed for training astronauts underwater to simulate space gravity for the astronaut's extravehicular activities (EVAs). (Photo by Boris Horvat/AFP Photo)

View of an American marine as he lies in a foxhole and whistles at a husky, one of the scouting dogs used during the landing on Guam, August 1944. (Photo by W. Eugene Smith/Time & Life Pictures/Getty Images)

In this photo taken Wednesday, March 8, 2017, a hospitality staff member pose for photos near the shadow of a tall light pole near the Great Hall of the People where a plenary session of the National People's Congress is held in Beijing, China. (Photo by Ng Han Guan/AP Photo)

A U.S. Marine leads training on a shooting range in France in an undated photo taken during the First World War. (Photo by Reuters/Courtesy Library of Congress)

An opposition activist clashes with the police during a march against Venezuelan President Nicolas Maduro held on May Day, in Caracas on May 1, 2017. Security forces in riot vans blocked off central Caracas Monday as Venezuela braced for pro- and anti- government May Day protests one month after a wave of deadly political unrest erupted. (Photo by Federico Parra/AFP Photo)

A supercell thunderstorm develops, May 8, 2017 in Elbert County outside of Limon, Colorado. With funding from the National Science Foundation and other government grants, scientists and meteorologists from the Center for Severe Weather Research try to get close to supercell storms and tornadoes trying to better understand tornado structure and strength, how low-level winds affect and damage buildings, and to learn more about tornado formation and prediction. (Photo by Drew Angerer/Getty Images)

Two women wearing nun outfits drink beer while watching the 2014 Tim Hortons Brier curling championships in Kamloops, British Columbia in this March 8, 2014 file photo. Although some people might conclude that a curling event could produce a dull atmosphere, it is actually far from it. Some of the most energetic and loyal fans are committed to showing their colours at tournaments around the world. There was a lull in the games that were being held on this day and I remember spotting these nuns sitting in their seats earlier. Although them just sitting there didn't produce a picture, I kept my eye on them for the entire match. As soon as I spotted them with beer in their hands, I slowly turned my camera towards them and waited for them to take a drink. One of the challenges of shooting this image was to not have everyone notice me taking the photo. I had a longer lens on and was right in the middle of the rink. I slowly turned my lens, not to make my intentions too obvious, and waited until they drank from their beers together. (Photo and caption by Ben Nelms/Reuters)

Indian artist Sudarsan Pattnaik works on a sand sculpture depicting drowned Syrian boy Aylan Kurdi at Puri beach, some 65 kilometers away from Bhubaneswar, on September 4, 2015. Charities helping refugees saw a surge in donations on September 4 across Europe as people shocked by the heart-rending images of a drowned Syrian boy on a Turkish beach dug deep to help out. The photos of the lifeless body of three-year-old Aylan Kurdi, lying on a beach in Bodrum, Turkey, have triggered a wave of emotion across the continent, despite deep divisions among European governments on how to deal with the crisis. (Photo by Asit Kumar/AFP Photo)