Nikola Tesla (/ˈtɛslə/ TESS-lə; Serbian Cyrillic: Никола Тесла, pronounced [nǐkola têsla]; 10 July [O.S. 28 June] 1856 – 7 January 1943) was a Serbian-American inventor, electrical engineer, mechanical engineer, and futurist best known for his contributions to the design of the modern alternating current (AC) electricity supply system.