If you have somewhere that is ‘home’, somewhere you spent long enough for it to have permanently imprinted on you, you can sometimes go back there and find that you’re able to speak in shorthand. There’s a pool of shared memories to refer to. But collective memory operates on a wider scale too - a national scale, continental even. Folk tales which span the entirety of Northern Europe form part of our collective memory, for example. Our entire culture rests of a foundation of collective memory, otherwise known as history. History, like memory, can be unreliable.