memory

I was walking up to the parking garage in Monterosso the other day when I caught a whiff of something- a combo of burning wood, pine trees, post-rain humidity and springtime- that took me back to when I was 6 years old on a family trip to Estes Park, Colorado. I don't think that we were actually in Estes Park at the time. We must have been on our way there or on our way back. Anyway, we were in a motel in Colorado and it was rainy and pine-tree smelling and fresh like spring here in Italy. It brought me back to an exact moment, one in which I was walking from our cabin to the lodge to play with their dogs. It started raining and I got stranded there and mother couldn't find me. I wasn't scared though. That must have been at least 30 years ago.
Another, less romantic, smell that pops up every so often is something- I have no idea what- that was used to clean the bathrooms in my elementary school in La Marque, Texas (NOT my elementary school in Galveston). Again, at least 30 years ago.
What is it about smell that so vividly evokes exact moments in one's past to present themselves with such clarity and definition that you're 'there' again.