In 1887 Nikola set up his own company, and was able to lodge two patents for applications related to the induction motor and polyphase AC power systems. These achievements gave a certain notoriety to Nikola, who was invited to speak at the American Institute of Electrical Engineers; he was lucky, since at that conference was present also George Westinghouse, owner of a growing electrical company. Tesla started so to work with Westinghouse who, buying also Tesla’s patents, was able to enter in competition with Edison: the “war of the currents” (DC versus AC) had entered its defining moment. During those years, Nikola worked hard in his laboratory, making more and more discoveries such as a predecessor of the current fluorescent tube, and investigated many physical phenomena such as X-ray and vacuum tube.

During the World’s Columbian Exposition, held in Chicago in 1893 to celebrate the 400th anniversary of Christopher Columbus’s arrival in America in 1492, Tesla gave a practical and amazing demonstration of the alternating current electricity: George Westinghouse and Tesla introduced the public to electrical power by illuminating the exhibition.

In 1895, Tesla designed the first hydroelectric power plant in Niagara Falls, which decided the ultimate success of alternating current and polyphase systems. The following picture shows the Monument dedicated to Nikola Tesla at Niagara Falls, New York.

Another great creation from Tesla is the Tesla coil (later used in radio and television sets), that he invented in 1891, the same year when he became an American citizen. At the same time, Tesla made also some relevant discoveries in the field of radio, more precisely with Hertzian waves, such as, for example, a way to transmit electrical energy in the upper atmosphere (patented in 1897). Then, in 1898, he gave a demonstration in New York City of a remote control wireless system: he was able to provide commands to a boat, basically steering and propulsion controls, by means of a radio device.

In 1899 Tesla moved to Colorado Springs (Rocky Mountains) to set up a new research laboratory with the purpose to work with high voltage and high frequency alternating current. The Colorado Springs Tesla Coil was even able to generate a spark over 135 feet long: the spark could be seen (and the produced noise could be heard, as well) from a distance of over 20 miles. Here is a famous image of Nikola Tesla working at the Colorado Springs laboratory.

Between 1901 and 1905, with the financial support provided by J. P. Morgan, Tesla built the Wardenclyffe laboratory, nearby Long Island, with the famous tower used for broadcast transmissions (187 feet high). In its original concept, the tower was planned to transmit both signals and power, without wires, to any point on the Earth. Unfortunately, due to lack of funds, the project could not be completed, and the tower was disused in 1917. The following picture shows the imposing Wardenclyffe tower.

In the following years, Tesla did many other new discoveries, until 1934, when he moved to his final residence, room 3327 of the Hotel New Yorker. In the last few years Tesla’s popularity has been increasing also among common people, thanks to many books, articles, and TV programs dedicated to him. One of Tesla’s ideas that seems to attract many people is the so-called “death ray”. The death-ray is basically a concentrated beam of microscopic particles moving at a speed close to the speed of light; according to Tesla, the death-ray would have knocked out enemy airplanes in a range of hundreds of miles providing defense and security for any country. As far as we know, the death-ray has remained a theoretical idea, even though its principle can be associated to some type of modern weapon.