War clouds loomed as the 'Thirties drew to a close. Pan Am worked closely with the U.S. government to secure and maintain vital air routes in a world increasingly fraught with danger. When war did come to America, vital supplies, personnel, and communications were delivered thanks to Pan Am's crews and aircraft, radio facilities, training schools, and airfield construction. In the Pacific, down the length of Latin America, across the Atlantic to Africa, and across the "roof of the world" into embattled China, Pan Am contributed substantially to Allied victory.