This is electronic music in a way you've never heard before: two, huge, solid-state musical Tesla Coils playing Edvard Grieg's "In the Hall of the Mountain King." Watch this video as these two giant coils play this famous piece.
Each electrical coil in this video can generate a 13 foot spark. This equates to about 500,000 volts of electricity. What appears to be a continuous burst of sparks are actually a specific number of sparks generated per second, carefully modulated to vary the tone produced and create the music you hear in the video.
A Tesla Coil produces dramatic flashes of high voltage electrical resonance. The low-current, high frequency electricity produced by the coils were invented by Nikola Tesla around 1891.
As they explain on their Youtube page:
The primary drive system for the coils consists of high power semiconductors arranged into an H-Bridge switching configuration. During a spark event, the coil is pulsed on for a few hundred millionths of a second. During this short time, thousands of amps circulate within the primary tank circuit and the energy is coupled into the secondary resonator through magnetism.