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)

From the “Paradise Revisited” story in the November 2013 issue of National Geographic magazine, this image is a beautiful vision of father and son fishermen as they move through the multicolored coral gardens of Kembe Bay, Papua New Guinea, in a traditional outrigger canoe. (Photo by David Doubilet/National Geographic Creative)

A man carries his wife over an obstacle while competing in the Wife Carrying Championship to mark City Day in Krasnoyarsk, Siberia, Russia, June 25, 2016. (Photo by Ilya Naymushin/Reuters)

Selfie picture shows Swiss pioneer Bertrand Piccard during the last leg of the round the world trip with Solar Impulse 2 over the Arab peninsula July 25, 2016. (Photo by Jean Revillard/Bertrand Piccard/Reuters/SI2)

Laura Giombini of Italy reacts during the Women's Beach Volleyball preliminary round Pool D match against Jamie Lynn Broder and Kristina Valjas of Canada on Day 2 of the Rio 2016 Olympic Games at the Beach Volleyball Arena on August 7, 2016 in Rio de Janeiro, Brazil. (Photo by Shaun Botterill/Getty Images)

Rascal, and her brother Petey, were abandoned as pups near the railroad tracks in Union County, Arkansas. She is a pit bull cross and approximately 6 months old, in Arkansas, United States. These canine portraits will make any dog lover's day – and they're helping to get sheltered pups adopted at the same time. Kind-hearted photographer Tammy Swarek came up with the idea of dressing up rescue dogs to draw attention to their stories and help potential owners personally connect with them. (Photo by Tammy Swarek/Barcroft Images)

Aline, along with other rangers and park staff visit the gorilla's in the parks Mikeno sector, where the majority of the gorilla families live in Virunga National Park. Therefore there has been a surge of poaching and violence in the area. For the first time, women have taken up the most dangerous job in wildlife, becoming para-military rangers at the Virunga National Park in DR Congo. (Photo by Monique Jaques)

A Ukrainian serviceman fires a 2S7 Pion self-propelled gun during military exercises near the village of Divychky in Kiev region, Ukraine, October 21, 2016. (Photo by Valentyn Ogirenko/Reuters)