 the 70 million square miles of the Pacific, United States engineers are building secret bases to strike at Japan. No military secret the news, but where has the Japs puzzled? Today on islands that once held promise of paradise, US blue jackets go about the grim business of war. Ferrying fighter planes ashore. Scout planes and bombers concealed and camouflaged amid the palms of the island. Aviation gasoline, oil, and supplies. All the necessary equipment for invasion or defense. Waters, they chart a base for sea planes. Ashore, giant tractors blaze clearings among the palms. And they're soon made ready for action, from which the United Nations plan their offensive against Japan. US Navy nurses line up for inspection in their new summer uniforms. Every day, new legions are being called to active duty afloat and ashore. Ready to follow the fleet to any battle front, these traditional angels of mercy know but one code, service to humanity. Women, as always, the heroes of all wars. In Washington, the commander of the newly formed Women's Army Auxiliary Corps begins her duties. A housewife and mother, she will direct an army of 250,000 women. Women who will work behind the lines, relieving more men for combat duty in the field. The first call for volunteers brings thousands to recruiting stations. Upon passing rigid examinations, they will undergo intensive training, live like regular soldiers, under strict army regulations. American women signing up to fight shoulder to shoulder with their men. The commander at the capital. For the first time in history, the army now has an authorized army of women. In mountain country, a woman's motorcycle corps takes to the field. Trained as dispatch riders, they carry messages and first aid equipment to lonely outposts. Women of America serving on the home front and up of champions to take the field since the last Olympic Games features the American Athletic Union track meet at New York City. Finish of the 110-meter dash, and the winner is San Francisco's Harold Davis. In classic Greek style, America's champion heaving the 16-pound shot put nearly 60 feet. 110-meter high hurdles. Sports playing an important part in the physical training program for America's youth. Watch the youngster nearest the camera. A university student, he wins the title in 14 seconds. Paul Valter, they all talk about. Warmer damn. Only man ever to leap higher than 15 feet. Champion of the world. Par excellence. US Post Office inaugurates a fast new mail service for soldiers and sailors overseas. Letters written on special forms, four by five inches when folded, are stamped and posted like regular mail. Passed by the sensor is photographed on small rolls of 16-millimeter microfilm. A 100-foot roll of film can carry 1,500 individual letters. Quite a saving in cargo space when you realize that 150,000 letters that ordinarily filled 22 sacks will on microfilm take just one bag. On arrival, the letters are enlarged to readable size. Good news for servicemen overseas. These are the first pictures of America's great naval victory in the Pacific. Army, Navy, and Marine planes cooperating with the fleet surprise a Jap invasion force sent to capture strategic Midway Island, stepping stone to Hawaii and the North American continent. US planes roaring to the attack amid a rain of anti-aircraft fire. May cruiser fatally hit, maneuvering to get away. Dazed by the unexpected sea and air assault, the Jap seek desperately to escape Japanese ships. Cruisers, carriers, and destroyers crippled like this or sent to the bottom. A blow more than equal to the defeat Japan suffered in the Battle of the Coral Sea. Back in port, Admiral Nimitz, who directed the action, bestows medals for deeds of valor. They fought the strangest naval battle in history, a battle in which the ships were hundreds of miles apart. The stories told by these hero pilots may rewrite all textbooks on naval warfare. They proved again and again that war planes can blast battleships and transports. In one epic engagement, these men upset the balance of power in the Pacific. The lesson is learned. Today, American plants speed production of more and more giant bombers. For bombers like these played a devastating role, not only in winning the battles of Midway and the Coral Sea, but they're carrying their messages home to the Nazis. On a 24-hour mass production schedule, America giving wings to the greatest armada of fighting ships the world has ever known. And here are more men ready to fly them, midshipmen saluting the color girl, as families of naval cadets come to see their sons made officers of the fleet and the fleet air arm. They march in their final review, the cream of America's young manhood, their lives dedicated to uphold the tradition of the Navy. Inside the historic hall of the old academy, they receive their wartime commissions a year early. For ships and planes are waiting, America's all ocean Navy.