Harris & Ewing Inc. photographed people, events, and architecture, particularly in Washington, D.C., during the period 1905-1945. Photo: Tests of Curtiss Palne for Army, Single Control. Created by Harris & Ewing. Published in 1912.

A guard stands at Dityatki checkpoint, marking a 30 km (18-mile) zone around the Chernobyl nuclear power plant April 23, 2013. Ukraine will mark the 27th anniversary of the Chernobyl disaster, the world's worst civil nuclear accident, on April 26. (Photo by Gleb Garanich/Reuters)

Marenda Schipper and Patrick Boelsterli show of their bee beards at an annual competition at Clovermead Adventure Farm, Saturday August 10, 2013 in Aylmer, Ontario, Canada. (Photo by Dave Chidley/AP Photo/The Canadian Press)

Members of the Women's Fire Brigade with their Chief Officer, March 1916. (Photo by Topical Press Agency)

A masked protester talks to a soldier during clashes after the funeral of Brig. Gen. Wissam al-Hassan October 21, 2012. Lebanese soldiers fired guns and tear gas to push back hundreds of protesters who broke through a police cordon and tried to storm the government headquarters in Beirut. (Photo by Hussein Malla/Associated Press)

U.S. Park Police work to keep people away from the area surrounding the Washington Monument after a 5.8 magnitude earthquake struck the east coast August 23, 2011 in Washington, DC. Police officers said that unidentified material had fallen off the Washington Monument as a result of the earthquake. All the monuments and buildings along the National Mall have been evacuated and closed. (Photo by Chip Somodevilla/Getty Images)

Soldiers, including two recruits who have brought some chickens, at Victoria prepare to board the train for the battle front. (Photo by Hulton Archive/Getty Images)