A couple of these towers have first been built by Nikola Tesla - the man himself, while testing a possibility of the transmission of electric current through the Earth's core. By some erroneous methodology, he thought he succeded and began publishing bragging articles about his 0% loss transmission equipment.

That was dead wrong. However, did manage to build a Tesla Tower - a tower made up of a stack of hand-made transformer coils that concentrated the potential in a small globe on the top of the tower. This generated an electric voltage of 2 MILLION VOLTS!

It is worthwhile to note that even the extremely experienced professionals would still need some CAD tools to do the same. Namely, most of the reproducers that weren't following Tesla's schemes exactly as they were done experienced a meltdown of their tower.

In the late 1950s and throught the 1960s, the RAF tested the Tesla Tower. What happens often is that a ball of plasma appears because of extremely high voltage. Needless to say, you don't want to be near when this happens.

This was only one of the many successful Nikola Tesla's experiments in resonance. One of his experiments in this field produced a demolition of a whole building block in New York.