I've read that our sense of smell is located in the most primitive part of our back-brain, where our animal instincts are situated. Once, it was vital to our survival, and that is why we "remember"smells and associate them strongly with particular times and places. You can detect a smell that you haven't encountered in many decades, and instantly remember where and when you smelled it before. Once I caught a scent in a completely unfamiliar setting. It was that of a medicinal salve that had been applied to me as a child in 1953, when I was 6 years old. It brought memories flooding back of the time and place and circumstances, after almost 60 years. I would not have been able to recall them without that scent.