Fun Fact: Behind Your Nose

On the roof of the nasal cavity (the space behind your nose) is the "olfactory epithelium," which contains millions of receptors that sense odor molecules. Through the air, odor molecules drift into the nasal cavity and stimulate some of the receptors, which then stimulate the brain to recognize that odor from among the many thousands of different smells cataloged in the brain.

Source: kidshealth.org