Have you ever noticed how a smell can immediately to transport you back to an event, place or circumstances where you first encountered it? I think that it has long been recognised that out of our five senses, smell is one of the most powerful - particularly in evoking memories.
I had such an experience of this effect last night when I was washing my kids, when I opened a tube of soap i've not used before. It was Mr Men soap - and it had a peculiar fruity smell. It immediately reminded me of my first flight to Russia on an Ilyhshin 76 Aeroflot flight in 1988. I can't recall exactly what the source of the smell was on the plane (because I don't think I knew at the time), but I attributed it to the smell of the free fruit drink served on the flight - it was billed as "lemonade" but it neither looked nor tasted like lemonade - it was a dark colour which made it look more like apple juice. It was either that or the fuel smell in the fuselage, or perhaps both. I dunno, but I was immediately taken back to that flight as soon as I smelled this soap.