Dr. P.A. Smithe was sent by the American Red Cross as a doctor and surgeon to work at a hospital in Vienna. He sailed to Europe in December 1915 and returned home in August 1916, according to his daughter, who donated his images to the National World War I Museum. Photo: Turkish army, including cavalry, infantry and artillery. (Photo by Dr. P.A. Smithe/National World War I Museum, Kansas City, Mo.)

RAF volunteers from stations across the UK, who will be acting as the lining party during the Royal Wedding, practice drills in the Parade square at RAF Holton on April 26, 2011 in Aylesbury, England. The members will make up the Queen's Colour Squadron, and will be lining the route between Buckingham Palace and Westminster Abbey during the wedding of Prince William and Catherine Middleton on April 29, 2011. (Photo by Dan Kitwood/Getty Images)

Singer Ariana Grande (C) performs “Side by Side” during the 2016 American Music Awards in Los Angeles, California, U.S., November 20, 2016. (Photo by Mario Anzuoni/Reuters)

Piper Hoppe, 10, from Minnetonka, Minnesota, holds a sign at the doorway of River Bluff Dental clinic in protest against the killing of a famous lion in Zimbabwe, in Bloomington, Minnesota July 29, 2015. A Zimbabwean court on Wednesday charged a professional local hunter Theo Bronkhorst with failing to prevent an American from unlawfully killing “Cecil”, the southern African country's best-known lion. The American, Walter James Palmer, a Minnesota dentist who paid $50,000 to kill the lion, has left Zimbabwe. He says he did kill the animal but believed the hunt was legal and that the necessary permits had been issued. (Photo by Eric Miller/Reuters)

A performer takes part in a street parade as part of the opening ceremony of the Ibero-American Theater Festival in Bogota, Colombia, March 12, 2016. (Photo by John Vizcaino/Reuters)

A general view of a royal wedding themed window display at Agent Provocateur in Pont Street, Chelsea on April 29, 2011 in London, England. The marriage of the second in line to the British throne is to be led by the Archbishop of Canterbury and will be attended by 1900 guests, including foreign Royal family members and heads of state. Thousands of well-wishers from around the world have also flocked to London to witness the spectacle and pageantry of the Royal Wedding. (Photo by Adrian Murrell/Getty Images)

Kim Kardashian and Kanye West leave their residence in Paris, on May 23, 2014. (Photo by Kenzo Tribouillard/AFP Photo)

A newly-married couple takes a nap before their mass wedding ceremony at the CheongShim Peace World Center in Gapyeong, South Korea, Sunday, February 17, 2013. Some 3,500 South Korean and foreign couples exchanged or reaffirmed marriage vows in the Unification Church's mass wedding arranged by Hak Ja Han Moon, a wife of the late Rev. Sun Myung Moon, the controversial founder of the Unification Church. (Photo by Lee Jin-man/AP Photo)