Everyone who's heard of Nikola Tesla has probably seen photos of him holding fully-illuminated light bulbs in his hands, not connected to any wires whatsoever. After Tesla invented his Tesla Coil, it became very obvious that electricity could be transmitted wirelessly. However, the Tesla Coil system relies on something called near-field electromagnetic waves, which means there is a large power drop relative to distance. In order for Tesla to fulfill his dream of providing the world with free energy, he imagined that he could "pump" electromagnetic waves into the ground, which would resonate with the entire earth, providing limtless, wireless electricty for everyone. Tesla eventually went on to build the Wardenclyffe Tower based on his Tesla Coil findings, but history records that the project was abandoned before it could be fully tested. This video demonstrates some very interesting principles, such as alternating current, the Tesla Coil, and also longitudinal and transverse waves.