An ordinary smell can unlock a room that no longer exists.

Smell reaches memory by a shorter route than anything else. A particular soap or a cooked onion or a certain kind of dust can put you back in a kitchen that was demolished years ago, complete with the light and the voices and how old you were. Nothing else in your life restores a place that quickly or that completely.

If a smell catches you like that, let it finish rather than shaking it off. And if you can name it, keep a little of it: the same soap, the same tea. It is one of the few reliable ways back to somewhere you cannot otherwise visit.