A member of the United States Naval Academy freshman class crawls through trenches at the wet and sandy station during the annual Sea Trials training exercise at the U.S. Naval Academy on May 13, 2014 in Annapolis, Maryland. For 14 hours, the United States Naval Academy freshman class, also known as Plebes, worked as a team to complete many grueling physical and mental challenges that help prepare them for real-world experiences and reinforce leadership, bonds, trust, and teamwork. Of the challenges, they endured: a two-mile regimental run, ground fights, water tactics, aquatics challenges, and survival skills, amongst many others. (Photo by Patrick Smith/Getty Images)

People hold umbrellas as they walk past a flooded street in Taiyuan, Shanxi Province, China, July 19, 2016. (Photo by Reuters/China Daily)

Sheep are herded during the annual sheep parade through Madrid November 2, 2014. Shepherds parade the sheep through the city every year in order to exercise their right to use traditional routes to migrate their livestock from northern Spain to winter grazing pasture land in southern Spain. (Photo by Susana Vera/Reuters)

“What did I know about Chechnya before last week? For someone who grew up in the 1990s the very word Chechnya meant a string of grainy images on TV showing people in battered camouflage outfits, shooting at each other amid destruction and ruin. Fear, wahhabis, Shamil Basayev, terrorism, mountains: these were the words that used to spring to my mind when someone mentioned Chechnya”. – Maxim Shemetov. Photo: Special forces officers stand guard during a government-organised event marking Chechen language day in the centre of the Chechen capital Grozny April 25, 2013. (Photo by Maxim Shemetov/Reuters)

“The McDonnell Douglas KC-10 Extender is an air-to-air tanker aircraft in service with the United States Air Force derived from the civilian DC-10-30 airliner. The KC-10 was the second consecutive McDonnell Douglas transport aircraft to be selected by the US Air Force following the C-9 Nightingale. The similar KDC-10 is in service with the Royal Netherlands Air Force.”

Photo: A B-52G Stratofortress aircraft takes off with another B-52G close behind. Three cells of six B-52 and KC-10 Extender aircraft will takeoff seconds apart under combat conditions during the minimum interval takeoff exercise. The exercise is a part of an operational readiness inspection by the Strategic Air Command Inspector General Team. (Photo by USAF). 1998

Young Palestinians form an obstacle to be jumped over during a military-style exercise graduation ceremony organised by the Hamas movement, in Gaza City August 5, 2015. Thousands of young Palestinians joined Hamas military-style summer camps during school vacation in the Gaza Strip to prepare them to “confront any possible Israeli attack”, organisers said. (Photo by Suhaib Salem/Reuters)

Rescue specialists for USA-1 drill through a concrete slab to rescue a victim from the scene of a mock disaster area during a training exercise at the Guardian Center in Perry, Georgia, March 25, 2014. A week of field training, the first of its kind at the 830-acre training site, to be open to the media, began Monday with the arrival of USA-1 from Fairfax, Virginia along with its sister team in Los Angeles, California. USA-1 has been deployed by the U.S. Agency for International Development to 30 foreign disasters, including earthquakes in Haiti, Armenia and Iran, the tsunami in Japan and the typhoon in the Philippines. (Photo by Shannon Stapleton/Reuters)

U.S Army combat camera photographer Spc. Hilda Clayton took this photo July 2, 2013 that was released by the U.S. Army, that shows an Afghan soldier engulfed in flame as a mortar tube explodes during an Afghan National Army live-fire training exercise in Laghman Province, Afghanistan. The accident killed Clayton and four Afghan National Army soldiers. (Photo by Spc. Hilda Clayton/U.S. Army via AP Photo)