Tesla unfortunately got the credit for the creator of the light bulb stolen from him. Thomas Edison hired Nikola to improve the inefficient Edison Bulb. Edison offered Tesla a million dollar deal, and when Edison received Tesla new better lightbulb he cheated Tesla out of the money.
After his work was stolen Tesla still went on to do great things creating hydroelectric systems and being a founder in radio and motor systems. One of his most ambitious ideas was the Tesla tower. The idea was that by utilizing the Earth for energy it provide the energy for free. This plan was not completely thought out and went beyond the provided funding. This first major failure lead to the downfall of Tesla's sanity and life.
By the end of his life Tesla became critically mentally unstable. He was diagnosed as clinically insane and frequently talked about a white pigeon that loved him as he did her.