Radar (Radio Detection and Ranging) was a critical technology that helped the Allies win the Battle of Britain. The British 'Chain Home' system used radio waves to detect incoming German Luftwaffe planes long before they reached the coast, allowing the RAF to scramble fighters efficiently. A key breakthrough was the 'Cavity Magnetron,' a small device that could generate high-power microwaves, allowing radar units to be small enough to fit inside aircraft and ships. This development was so significant that some historians claim radar contributed more to the Allied victory than the atomic bomb.