 Nikola Tesla was an ethnic Serb born in 1856 in what is now Croatia. He became a citizen of the United States in 1891. Among many other inventions, he worked on how to send electromagnetic energy without wires. In 1891, he painted an alternator for creating current at some 10,000 Hz. It was also among the first equipment to reliably produce long-wave radio. In 1892, Tesla demonstrated in London the transmission of radio signals. His technology was aimed at delivering electricity without wires, but in the 1897 patent he filed in the United States, Tesla stated that the invention would obviously have many other valuable uses, as for instance when it is desired to transmit intelligible messages to great distances. In 1899, Tesla built a high-voltage transformer, which he was said could generate 300,000 watts of power and produce an artificial bolt of lightning some 40 meters long. Now known as a Tesla coil, the inventor called it a magnifying transmitter. The idea was not only sent electricity, but also to construct a worldwide system for radio transmissions. The first transmitter was built in 1901 at Wardenclyffe on Long Island. Tesla hoped eventually to provide a global navigation and broadcasting service, but the project was ended because of cost. Tesla was never able to realize his vision of a freely powered and connected world.