Nikola Tesla was a Serbian-American inventor whose ideas about electricity helped create the alternating-current system that powers homes and cities around the world today. He dreamed up hundreds of inventions and held around 300 patents worldwide, from electric motors to a radio-controlled boat he demonstrated at Madison Square Garden in 1898, decades before remote-controlled devices became common. He is remembered as one of history's most imaginative inventors, whose ideas were often far ahead of his time.