In many religions this content is:
In Paganism, the content is often dynamic. You go on a mental journey to experience the elements, or a god or goddess, or something else of deep spiritual significance. This can be very enriching.
It is easiest at first to follow a narrative written by someone else. Bill Anderton's Meditation for Every Day includes many evocative visualisations of this sort. For a CD of seven recorded journeys, it is well worth the effort of tracking down Marian Green's The Paths of Magic CD: write with sae to BCM-SCL Quest, London WC1N 3XX (no website).