If you’ve ever read a Highlights magazine, you’ve likely played the hidden picture game–the one where children are asked to find out-of-place objects like pencils hidden in trees and candy canes hidden in striped dresses. As I came across photographs from the Women’s Reserve Camouflage Corps, I was instantly reminded of the classic childhood time-killer. Only this time, instead of searching for a misplaced golf club in an illustrated drawing, I found myself staring at a real photograph looking for hidden women.

When the United States entered World War I in 1917, both men and women helped out in the war effort. Women worked in factories, joined the Red Cross, and participated in a number of military organizations. In New York City, a group of female art students joined the National League for Women’s Service and trained to serve in the Camouflage Department of the United States Navy.

Allied forces used camouflage in two very distinct ways during in World War I. The first, and more traditional way, was designed to conceal a soldier in their environment. The “rock suit,” for instance, was designed to keep the wearer safe from detection at a distance of ten feet. Similarly, the “observation suit” was designed so the wearer could blend in with the sky, and when needed, turn the suit inside out to blend in with snow and ice. Female students studied the environment, and apparently tested the suits, in New York’s Van Cortlandt Park before joining the Allied forces in France.

Women’s Camouflage Reserve Corps study anti-detection methods, camouflaged against the rocks at Van Cortlandt Park, New York. Local ID: 165-WW-599G-29. Women’s Camouflage Reserve Corps study anti-detection methods, camouflaged against the rocks at Van Cortlandt Park, New York. Local ID: 165-WW-599G-21.

Allied forces also utilized a technique known as “dazzle camouflage.” Dazzle camouflage was not intended to obscure but to confuse. Naval ships were painted in abstract patterns with bright colors to make it difficult for German U-boats to determine the speed and precise location of the ship. Beginning in March of 1918, the United States Navy painted a total of 1250 vessels with the unique design. Out of the 96 ships sunk by Germans after March 1918, only 18 of the ships were camouflaged.

In order to prepare for dazzle camouflage, artists in the Women’s Reserve Camouflage Corps practiced on a variety of subjects. The young women camouflaged an ambulance and a tank on the steps of the New York Public Library, and a War Savings Stamps Booth at the intersection of Broadway and 43rd Street. Most notably, the artists painted a full ship, the USS Recruit, in the middle of Union Square, New York.

Women Camouflage Land Battleship “Recruit” in Union Square, New York. Local ID: 165-WW-599G-8. Women Camouflaging the War Savings Stamps Booth at Broadway and 43rd Street, New York. Local ID: 165-WW-599G-41. Women Camouflage Land Battleship “Recruit” in Union Square, New York City. Local ID: 165-WW-599G-9.

The photos of the Women’s Reserve are some of the most fun and unusual that I’ve come across at the National Archives. Can you find all of the hidden women in the images below? Some are tougher than you might think!

Women’s Camouflage Reserve Corps, of the National League for Women’s Service, Study camouflage at Van Cortlandt Park, New York. Local ID: 165-WW-599G-21. Women’s Camouflage Reserve Corps, of the National League for Women’s Service, study camouflage at Van Cortlandt Park, New York. Local ID: 165-WW-599G-22. Members of Women’s Camouflage Reserve Corps studying anti-detection methods. Camouflaged on top of the rocks. At Van Cortlandt Park, New York City. Local ID: 165-WW-599G-39. Women’s Camouflage Reserve Corps, of the National League for Women’s Service, Study camouflage at Van Cortlandt Park, New York. Local ID: 165-WW-599G-21. Women’s Camouflage Reserve Corps, of the National League for Women’s Service, Study camouflage at Van Cortlandt Park, New York. Local ID: 165-WW-599G-18. Women’s Camouflage Reserve Corps studying anti-detection methods, camouflaged among the branches at Van Cortlandt Park, New York. Local ID: 165-WW-599G-30. Women’s Camouflage Reserve Corps, of the National League for Women’s Service, Study camouflage at Van Cortlandt Park, New York. Local ID: 165-WW-599G-19.

NARA is currently completing a large-scale project to digitize photographs and films from World War I, including these photographs from 165-WW, American Unofficial Collection of World War I Photographs, 1917-1918. Check back soon for updates on this project.