It seems to me that those cultures which have an oral rather than a written tradition have rather sophisticated ways of memorising certain things. Many of them are strongly attached to land which is the basis of not only their livelihood, but also their spiritual beliefs.
Basically, from my limited understanding, the land then acts as a “map” for many things, from the surrounding geography through to a “map” of their spiritual beliefs. As land has lots of identifying markers, this then acts as an aid to remembering most details of the lives of people from such cultural traditions.
