Model of the death beam at the Nikola Tesla Genius of Modern Electricity exhibition. The death beam was a theoretical particle beam or electromagnetic weapon first theorised around the 1920s and 1930s. The fictional gun emits microscopic, electrically charged particles. Nikola Tesla (1856-1943) was a Serbian American physicist and electrical engineer. He is known for designing the alternating-current (AC) electric system, which is the predominant electrical system used across the world today. Photographed at CaixaForum Zaragoza in Spain, in collaboration with The Nikola Tesla Museum of Belgrade.