![Descartes - Third Eye](https://www.bookofthrees.com/wp-content/uploads/2007/08/descartes-fig-32-third_eye.jpg)
The pineal gland was the last endocrine gland to have its function discovered. Its location deep in the brain seemed to indicate its importance. This combination led to its being a “mystery” gland with myth, superstition and even metaphysical theories surrounding its perceived function.