Women served on both sides of World War II, in official military roles that came closer to combat than ever before. The Soviet Union, in particular, mobilized its women: Upward of 800,000 would enlist in the Red Army during the war, with more than half of these serving in front-line units. British forces included many women alongside men in vital anti-aircraft units. And Nazi Germany followed suit later in the conflict, when its flagging fortunes required the nation’s full mobilization.

Of the four major powers in the conflict, only the United States resisted sending any women into combat. Still, thousands of American women did join the military in various capacities during World War II, upending generations of traditional gender roles and longstanding assumptions about female capability and courage.

Soviet women served as scouts, anti-aircraft gunners, tank drivers and partisan fighters, but the two most dangerous—and celebrated—roles they played were as pilots and snipers.

In the fall of 1941, with invading German forces threatening Moscow, Marina Raskova (known as the “Russian Amelia Earhart”) convinced Joseph Stalin to authorize three regiments of female pilots. The most famous was the 588th Night Bomber Regiment, whose pilots hit so many of their targets that the Germans started calling them the Nachthexen, or “night witches.” Using rickety plywood planes, the women of the 588th flew more than 30,000 missions and dropped more than 23,000 tons of bombs on the Nazis; 30 of them were killed and 24 received the Hero of the Soviet Union medal, the nation’s highest award for valor.

Though nearly 2,500 Soviet women were trained as snipers, many others took on the role without formal training. Assigned to infantry battalions, female snipers were tasked with targeting German frontline officers and picking them off as they advanced. One sniper, Lyudmila Pavlichenko (aka “Lady Death”), killed a confirmed 309 Germans, including 36 enemy snipers, in less than a year of service with the Red Army’s 25th Rifle Division. Wounded four separate times, she was taken out of combat by late 1942; the Soviet government sent her to the United States, where she toured the country with Eleanor Roosevelt. She was 25 years old.

In mid-1941, when the British military began using women from the Auxiliary Territorial Service (ATS) in anti-aircraft units, they made it clear that the purpose was to free up more men to fight; women were still barred from taking combat roles. The Blitz had just ended, but Germany’s Luftwaffe still ran bombing raids over London and across Britain throughout the conflict. ATS women (popularly known as Ack Ack Girls) served in mixed Royal Artillery batteries with men. Though they became skilled in spotting, or locating enemy aircraft, setting the range and bearing on the anti-aircraft guns and handling the ammunition, women were prohibited from actually pulling the trigger. As one gunnery assistant put it: “We did the same duties as the men. When they stood on guard all night they had their rifle, when we stood on guard we had a broom handle.”

Many ATS members were assigned to searchlight units, positioned around each gun complex to spotlight incoming German bombers for the gunners to take aim. Searchlights also lit the skies for returning British bombing crews and scanned the seas for approaching German vessels, among other vital tasks. Formed in October 1942 on the orders of Major-General Sir Frederick Pile, the 93rd Searchlight Regiment was Britain’s first all-female army regiment. It operated some 72 searchlights outside of London, each staffed by a dozen women (plus one man to turn on the generator and fire a machine gun, if necessary).

By war’s end, more than 74,000 British women were serving in anti-aircraft units. Overall, 389 ATS women were killed and wounded during the conflict. As Pile later wrote, “The girls lived like men, fought their lights like men and, alas, some of them died like men.”

While Adolf Hitler initially insisted that women remain at home during the war and focus on their roles as wives and mothers, Germany’s increasingly desperate need for resources would lead more than 450,000 women to join auxiliary military forces.

In July 1943, German war production minister Albert Speer convinced Hitler to authorize women to serve in searchlight and anti-aircraft units with the Luftwaffe, and as many as 100,000 German women would serve in this capacity by the end of the war. As with the ATS, they were fully trained in operating anti-aircraft guns, but were barred from firing them. According to an order Hitler issued in late 1944, no German woman was to be trained in the use of weapons. Nazi propaganda warned women in the auxiliary forces not to become flintenweiber, or “gun women,” a derisive term for Soviet women fighters. In the last, desperate months of the conflict, Hitler gave in and created an experimental women’s infantry battalion, but the war ended before it could be raised.

A total of 39 women would receive Germany’s Iron Cross for duty near the front, but nearly all of them were nurses. Among those who weren’t were Hitler’s test pilots Hanna Reitsch and Melitta Schiller-Stauffenberg, two of some 60 female pilots used to ferry Nazi flights in order to free up male pilots for active duty.

Much has been made of the way American women served on the homefront, powering the factories that enabled the United States to become “the arsenal of democracy.” As in past conflicts, tens of thousands of American women also served courageously as nurses, with more than 1,600 members of the U.S. Army Nurse Corps alone earning medals, citations and commendations. But many other women served the U.S. war effort in an active—and often dangerous—capacity. Though the United States did not send any women into combat during World War II, the conflict did see the nation take steps toward integrating women into the military in a new way.

After heated debate in Congress over the inversion of traditional gender roles implied by women’s enlistment in the armed forces, the Army became the first to enlist women, creating the Women’s Auxiliary Army Corps (WAAC) in May 1942. In July 1943, thanks to the efforts of director Oveta Culp Hobby, the WAAC was converted to regular army status as the Women’s Army Corps (WAC).

Influenced by the performance of female soldiers in Europe, Army Chief of Staff George C. Marshall authorized some in the WAAC to be trained on anti-aircraft batteries and searchlight units, like their British and German counterparts. But by mid-1943, he called off the experiment, fearing public outcry and Congressional opposition to the idea of women in combat roles. More than 150,000 women served in the WAC during the war, with thousands sent to the European and Pacific theaters. None saw combat, but their brave service would lead to greater acceptance of the idea of women into the military.

American women also took to the skies during World War II, as the U.S. Army Air Forces (predecessor of the Air Force) began training women to fly military aircraft in order to free male pilots for combat duty. In the Women Airforce Service Pilots (WASP) program, women flew B-26 and B-29 bombers and other heavy planes between factories and military bases around the country; tested new and repaired planes; and towed targets for gunners in the air and on the ground to practice shooting, using live ammunition.

By December 1944, when Congress mandated the closure of the elite program (more than 25,000 women applied during the war, but only 1,100 would end up serving), 38 WASP pilots had lost their lives due to plane crashes or other accidents in the line of duty. Program records were classified, and all official traces of the program disappeared until the late 1970s, when President Jimmy Carter finally granted the pioneering female aviators the status of U.S. military veterans.