...when harmony can cause destruction...

Tuning fork picture.
A tuning fork. Its resonance frequency defines a certain pitch used by musicians.

What is resonance?

According to Wikipedia, resonance is defined as follows:

"In physics, resonance describes the phenomena of amplification that occurs when the frequency of a periodically applied force is in harmonic proportion to a natural frequency of the system on which it acts. When an oscillating force is applied at a resonant frequency of a dynamical system, the system will oscillate at a higher amplitude than when the same force is applied at other, non-resonant frequencies."

Depending on whether the effect is wanted or not, resonance can be good or bad.
Check out the following situations in which resonance occurs.

Picture of Tacoma Bridge.
The Tacoma Narrows Bridge collapsed do to resonance effects caused by winds in 1940.

Overtone singing uses frequencies that are multiples of the frequency sung.
These so-called overtone frequencies are amplified by resonance in the skull
so that one single person can sing several tones at a time.