My mom and dad would make the 5 hour trek from the Gulf coast to the hill country about every 6 weeks. They didn't want to miss a single milestone of their grandson's development.
They'd arrive in a flourish of hugs and kisses and inevitably my mom would throw open her suitcase right there in the living room, unable to wait another second to bestow gifts upon her grandson.
And in that moment, out of their luggage would waft the scent of the Lower Rio Grande Valley. Green and fertile, dank and earthy, it is powerful imprinting. Always catching me off guard, the aroma would whisk me back to the only other home I'd ever known, a small frame house surrounded by lush subtropical greenery.
I've often thought that something of this experience is how a sea turtle returns to its beach from across the ocean's great expanse.
A more practical use of this olfactory association -- it makes me the human litmus test for spotting a bottle of corked wine: smells just like home.