A soldier shares a tender moment with his girlfriend while other soldiers rest during a rehearsal of a military parade a few days before the Independence Day in Kiev, Ukraine, Monday, August 22, 2016. Ukraine to mark the 25th anniversary of the Independence Day on August 24. (Photo by Efrem Lukatsky/AP Photo)

Afghan air force 2nd Lt. Niloofar Rhmani walks the flight line at Shindand Air Base, Afghanistan, prior to her graduation from undergraduate pilot training, on May 13, 2013. Rhmani made history on May 14, when she became the first female to successfully complete undergraduate pilot training and earn the status of pilot in more than 30 years. She will continue her service as she joins the Kabul Air Wing as a Cessna 208 pilot. (Photo by Senior Airman Scott Saldukas/USAF)

Ice swimmer Klaudia prepares to swim in a filled up water kettle in an ice cave inside the Nature Ice Palace, with a hight of 3,250 meters (10,663 feet) above sea level, at Hintertux Glacier near Hintertux, some 480 kilometers (298 miles) western of Vienna, Austria, 28 July 2018. (Photo by Christian Bruna/EPA/EFE)

An American family with a carved pumpkin illuminated by a candle to celebrate Halloween. (Photo by Sherman/Three Lions/Getty Images). Circa 1955

A tourist jumps inside an upside-down house at Fengjing Ancient Town, Jinshan District, south of Shanghai, May 1, 2014. The upside-down house was built as a tourist attraction using everyday household items and furniture. (Photo by Aly Song/Reuters)

Russian servicemen drive a partially covered T-14 Armata tank along a street before a rehearsal for the Victory Day parade in Moscow, Russia, April 29, 2015. Russia will celebrate the 70th anniversary of the victory over Nazi Germany in World War Two on May 9. (Photo by Maxim Zmeyev/Reuters)

Canadian soldiers from the Royal 22nd Regiment take up a position during a non-combative extraction operation in a simulated village as part of Rim of the Pacific (RIMPAC) 2016 exercise held at Camp Pendleton, California United States, July 11, 2016. (Photo by Mike Blake/Reuters)

The sun streaks through the fall foliage at sunrise along the Potomac River in Arlington, Va., Wednesday, November 4, 2015 on a warm fall day in the nation's Capitol area. (Photo by J. David Ake/AP Photo)