In the middle of a Hollywood party in 1940, actress Hedy Lamarr sat at a piano with composer George Antheil. While guests chatted about movies, she was sketching a new kind of radio signal. She had just heard that a British torpedo had missed its target because the enemy jammed its guidance frequency. 'What if the signal jumped between frequencies?' she whispered to Antheil. He nodded, thinking of player-piano rolls that could control a sequence of notes. That night, they began designing a system that would change warfare forever.

Hedy Lamarr was born Hedwig Kiesler in Vienna, Austria, in 1914. Her father was a banker who loved technology, and he often took her on walks to explain how streetlights and trams worked. By age five, she could take apart a music box and put it back together. But her beauty led her to acting, and by 19 she had starred in a controversial film. She fled an unhappy marriage to a weapons dealer and escaped to London, then Hollywood. There, she became a famous movie star, but her mind never stopped tinkering.

During World War II, Lamarr wanted to help the Allied war effort. She knew that radio-controlled torpedoes were easily jammed because they used a single frequency. If a ship could change frequencies in a pattern that the enemy didn't know, the torpedo would stay on course. But she was an actress, not an engineer. Many people dismissed her ideas. 'Why don't you use your face to sell war bonds?' they said. Instead, she teamed up with Antheil, who understood mechanical synchronization. Together, they created a system using 88 frequencies—the same number as a piano's keys.

Her father was a banker who loved technology, and he often took her on walks to explain how streetlights and trams worked.

In 1942, Lamarr and Antheil received a patent for their 'Secret Communication System.' But the US Navy rejected it, saying the mechanical parts were too bulky. Lamarr was disappointed but didn't give up. She used her fame to raise millions in war bonds and continued inventing at home. She once set up a chemistry lab in her dressing room. Decades later, in the 1960s, the Navy finally used her frequency-hopping idea. It became the basis for spread-spectrum technology, which today powers Wi-Fi, Bluetooth, and GPS. Hedy Lamarr died in 2000, but her legacy lives on in every wireless device.

She once said, 'Any girl can be glamorous. All you have to do is stand still and look stupid. But I wanted to be useful.' Her invention was decades ahead of its time. A fun fact: the patent for her frequency-hopping system was only rediscovered in 1997, when she received a special award from the Electronic Frontier Foundation. She was 82 years old. That night at the piano, she had planted a seed that would connect the world.