Nurses at a war hospital posing for a photograph, 1914-1918.

UNITED KINGDOM - SEPTEMBER 21: Postcard showing nurses at Queen Mary's Orthopaedic Hospital in Roehampton, UK, during World War I. A total of 1.6 million British servicemen were wounded in the course of the First World War. In 1914, there were two uniformed nursing organisations open to British women; the First Aid Nursing Yeomanry (FANY) and the Voluntary Aid Detachments (VAD). Initially the British Army would not allow women nurses to serve at the front, but by 1915, volunteers over the age of 23 were permitted to serve at field hospitals on the Western Front as well as in Mesopotamia and Gallipolli. In addition to the nurses serving at the front, many more worked tending the wounded brought back to hospitals in Britain. (Photo by SSPL/Getty Images)