Multiple exposure publicity picture of Tesla sitting in his Colorado Springs laboratory with his “Magnifying transmitter” generating millions of volts and producing 7-metre (23 ft) long arcs.

The magnifying transmitter is an advanced version of Tesla coil transmitter. It is a high power harmonic oscillator that Nikola Tesla intended for the wireless transmission of electrical energy. In his autobiography, Tesla stated that “…I feel certain that of all my inventions, the Magnifying Transmitter will prove most important and valuable to future generations.”

I particularly like how casually Tesla is just sitting there as electricity is exploding around him.

But, then, according to historical anecdote that was pretty much de rigeur for Nikola Tesla.

Via Wikipedia.