Tesla's system of alternating current (AC) beat Thomas Edison's direct current (DC) to power the world.

Edison's DC could only travel about a mile before dying out. You would need power plants on every street corner. Tesla's AC could travel hundreds of miles over thin wires. Westinghouse bought Tesla's patents and lit up the Chicago World's Fair in 1893. That proved AC was the future. It is the reason we can plug things into walls today.