Nikola Tesla needed ambient electricity to make his wireless inventions work. So he created the Tesla coil.
At the 1893 Columbian Exposition in Chicago, 160,000 light bulbs lit up the evening sky over Chicago.
During the last part of the 19th century, George Westinghouse had made his fortune through his invention, the railroad air brake.
Nikola Tesla stunned audiences when he wirelessly lit up glass tubes filled with gas. He called it cold light.