Young Nikola Tesla came to the United States in 1884. Tesla would spend the next 59 years of his productive life living in New York. Tesla set about improving line of dynamos while working in Edison's lab in New Jersey. It was here that his divergence of opinion with Edison over direct current versus alternating current began. This disagreement climaxed in the Battle of Currents as Edison fought a losing battle to protect his investment in direct current equipment and facilities.