We may not know how to describe it very well, but we all recognize "old person" smell whenever it happens to grace our nostrils. But while the scent may be ubiquitous, its causes are a little less clear.
Your senses help you navigate through the world more than you might realize. And what about ESP? These pictures take you through the world of senses from your nose and the inside of your ear to the exploration of mind reading.
Smell is a basic sense, but scientists are still exploring how it works. Why are researchers, developers and even government agencies so curious about smell? What makes a seemingly simple sense so tantalizing?