For Hedy Lamarr, acting in films alongside Clark Gable, Spencer Tracy, and Jimmy Stewart was just a day job. By night, the Vienna native pursued her true passion: planning a secret communication system with radio frequency hopping that the Navy could use to fire torpedoes during the 1940s. The U.S. Navy did not take Lamarr’s mobile communication idea seriously, advising her to stick to moving images. But her blueprint ended up laying the foundation for today’s irreplaceable tech like WiFi, GPS, and Bluetooth.