In WWII, the Allies used an elaborate system of spies, double agents, and information leaks to keep the Abwehr, the German spy organization, from anticipating the invasion of Normandy. One of their key strategies was the First U.S. Army Group (FUSAG), the largest army that never existed.
Historians have referred to children in the Middle Ages as “little adults” and children at the time were routinely involved in conflict. The “rights of the child” are relatively contemporary, however, children continue to be recruited and trained at very young ages in a practice woven deep in the history of many cultures.
Mosquito abatement programs pioneered by William Gorgas in Cuba and Panama led to immediate relief from yellow fever. Later, his discoveries played a major role in WWII, and still help with control of the disease today. We have a vaccine, developed by Max Theiler, but there is still no cure and outbreaks occur.