Tesla light(n)ing

Air is an inefficient gas from a lighting point of view, but it can still emit impressive amounts of light when excited with hundreds of kilovolts and more, like in the case shown in the picture above. Here, a 20-kW solid-state Tesla coil was placed on top of a building at the university during an art exhibit. Power fed to the transformer's secondary was modulated at acoustic frequency in order to generate light flashes and arc patterns at the rhythm of music.