In this November 2, 2017 photo, Mathew Fulkerson and his wife Leigh Ann pose at their Subterra Airbnb located in a former underground missile silo base near Eskridge, Kan. It was designed to house a nuclear warhead six decades ago – but now, this Cold War silo is the perfect spot for a mini break at just $133 a night. (Photo by Thad Allton/The Topeka Capital-Journal via AP Photo)

German field telegraph operators at work in Warsaw. (Photo by Hulton Archive/Getty Images). 1st October 1914

Russian soldiers write home while serving on the Eastern Front during World War I, circa 1915. (Photo by Hulton Archive/Getty Images)

U.S. Marine Lt. Ben Reid from 1/2 Charlie Company of Task Force Tarawa waits to be medivaced after being hit with shrapnel and a machine gun round, in the southern Iraqi city of Nasiriyah, on March 23, 2003. The Marines suffered a number of deaths and casualties during gun battles throughout the city. (Photo by Joe Raedle via The Atlantic)

An Israeli tank moves into position in the Israeli controlled Golan Heights during fighting between forces loyal to Syrian President Bashar Assad and rebels in the Druze village of Khader in Syria, Tuesday, June 16, 2015. As many as 20 members of the Druze minority sect were killed last week, the deadliest violence against the Druze since Syria's conflict started in March 2011, sparking fears of a massacre against the sect. (AP Photo/Ariel Schalit)

Rebel fighters from the Ahrar al-Sham Islamic Movement fire a heavy machine gun during what they said was an offensive to take the northwestern city of Idlib March 24, 2015. (Photo by Khalil Ashawi/Reuters)

Newly-wed Syrian couple Nada Merhi, 18, and Hassan Youssef, 27, have their wedding pictures taken in front of a heavily damaged building in the war ravaged city of Homs on February 5, 2016. A Syrian photographer thought of using the destruction of Homs to take pictures of newly wed couples to show that life is stronger than death. (Photo by Joseph Eid/AFP Photo)

Reenactors playing the roll of Kentucky volunteers, fighting for the United States, fire muskets during a reenactment of the Battle of New Orleans in the War of 1812, marking its bicentennial in Chalmette, Louisiana, January 10, 2015. The participants, some of whom have travelled thousands of miles to join in the event, recreated the five clashes that comprise the battle, which some historians say was key in making the British honor the terms of a peace treaty signed in late 1814. (Photo by Lee Celano/Reuters)