Answer: Earthquakes

During the late 1890s, accomplished researcher Nikola Telsa constructed a small oscillation engine at his laboratory located at 46 E. Houston Street in New York City. In the course of Tesla’s conducting experiments with the oscillation engine, the engine began to vibrate at frequencies that aligned with the resonance frequency of surrounding buildings.

Resonance frequency is the frequency at which an object (be it a musical instrument, a block of wood, or an entire building) begins to vibrate in response to an external frequency source (such as Tesla’s oscillation engine). As such, the occupants of the nearby buildings experienced shocking tremors and vibrations as the energy from Tesla’s engine spread through the surrounding structures. In their panic over a perceived Earthquake or even more inexplicable event, they called upon the authorities.

Shortly before the police finally isolated Tesla’s laboratory as the source of the disturbance, the engine began to vibrate at the perfect frequency to resonate within the laboratory. Tesla, with his lab shaking around him, realized the danger he was putting himself and everyone else in, and smashed the device with a sledgehammer to put an end to the shaking.