Tesla coil and Tesla tower
A Tesla tower what you mention is the Tesla magnifier. It is different from Tesla coil, it has an additional tank inductor. 







simulate this circuit &ndash; Schematic created using CircuitLab







simulate this circuit

The original purpose was to generate a standing wave in the Earth crust. With a suitable resonance receiver it should be possible to tap the energy at large distance (worldwide). The transmitter would 'sense' the load directly as classical wired generator. Tesla calculated that the loss would be typically 5% which is not bigger than traditional powerline loss.