Nikola Tesla is the father of modern electricity and the inventor of the radio. He was among the most famous scientists or engineers of the 20th century, but his fame was tarnished by far-out claims he made regarding his technology. At one point or another claiming to have harnessed cosmic rays for power, built a "death ray" that could take out planes from miles away, and work on electric transmission devices that would have supposedly allowed consumers to power devices simply by sticking a wire into the ground. His claims have largely subsequently been championed by practitioners of pseudoscience and the occult, further tarnishing Tesla's legacy, but many sober scientists and engineers still regard Tesla as an inspiring figure and a great inventor.
Nikola Tesla was born 10 July 1856 in the village of Smiljan near Gospić, which was then a part of the Austrian Empire, now a part of Croatia. On 6 June, 1884, Nikola Tesla arrived in New York City, where he mostly remained for the rest of his life until he died impoverished on 7 January, 1943, at the age of 86. Although Tesla made millions throughout his life through the sales of his devices, he was poor with finance and spent huge sums of money on gargantuan electrical engineering projects that never bore fruit. However, for many, this eccentricity only added to his charm. His eccentricity, besides his numerous contributions to science and engineering, was arguably the main driving force for his worldwide fame throughout the early 20th century.
The number of scientific and engineering contributions made by Nikola Tesla was truly enormous. He invented the notion of alternating current, which, contrary to the beliefs of many powerful men at the time, including Thomas Edison, would never be more useful than the direct current. The modern power grid is based on alternating current. Tesla invented the AC motor, which helped jumpstart the Second Industrial Revolution in the 1900s and 1910s. He invented numerous systems for the wireless transmission of power and signals, the basis for the radio. He pioneered the tesla coil, the arc lamp, bladeless turbines, x-ray tubes, the spark plug, and fluorescent lights. The fundamental scientific unit of magnetism is named the tesla in his honor.