Every town has a sound you stopped hearing: a train, church bells, a highway. Listen for yours tonight.

Repeated sounds get filtered out so they do not use up your attention, which is efficient and slightly sad. The train, the bells, the motorway hum have been part of every day you have spent here and have turned into silence. They are also the exact thing you will recognise in ten years from two notes.

Stand outside tonight for three minutes and find yours. Name it. If you can, record ten seconds of it on your phone and keep the file somewhere safe. People who have moved away will tell you this is the thing they wish they had taken with them.