A crying baby.

The neighbor's dog at 3am.

A ringing cell phone in church.

Some of the most annoying sounds on earth.  But when it comes to the sounds that get the biggest reaction from your body, it's the screech of a knife against a glass bottle (gives you chills just thinking about it!)

Researchers at the University of Newcastle in England said the reaction is two-fold:

Unpleasant noises not only increase blood flow in the brain's auditory cortex, where sound is processed, but also trigger the amygdala, a primitive region of the brain that processes emotions.

What are the Top 5 harshest sounds? Click here to find out.