In 1884, an up-and-coming European inventor named Nikola Tesla arrived in New York. Haunted by vivid premonitions that guided his creations, Tesla was said to have designed a “death ray”—a weapon too dangerous and powerful to actually be built. When he died alone in a New York hotel in 1943, officials seized his papers, fueling rumors that many of his radical inventions were buried or stolen. Ideas that the world simply isn’t ready for, even today.