I recall as a teenager catching a whiff of tar and instantly recalling a memory from when I was very young (somewhere between 2 and 5) of being in a parking garage with the same smell. I can still "see" the garage and even smell it, but that's it. I have no other contextual clues to know when or where it happened (unlike my earliest memory of being in a large city---it was Chicago where we lived when I was 2, but I only know that because of what my parents have said over the years).