Alternating current
In 1884 he arrived in the USA and briefly worked for Thomas Edison. Edison was building direct-current networks, which couldn't carry power very far. Tesla designed a polyphase alternating-current system and a brushless induction motor. His patents were bought by the businessman George Westinghouse.
The War of the Currents
In the late 1880s Edison and Westinghouse fought bitterly over which current would win out. It was settled by the World's Fair in Chicago in 1893, which was lit by alternating current, and by the power plant at Niagara Falls, which from 1896 sent electricity to Buffalo, roughly 40 km away. Alternating current is still what comes out of our sockets today.
Wireless dreams
In 1898 in New York he demonstrated a radio-controlled boat, a forerunner of remote controls and of drones. On Long Island he built the Wardenclyffe Tower for the wireless transmission of both messages and power, but the money ran out. In 1943 the US Supreme Court struck down Marconi's key patent on the Radio, among other things because of Tesla's earlier work.
A name that lives on
The unit of magnetic flux density is named after Tesla, as is the car maker Tesla. Wireless charging of phones relies on induction, which Tesla was experimenting with more than 130 years ago.