What's the name for this type of meditation??

Back in highschool we 2 times had what we in danish and roughly translated into english called a "dream-journey".
We would lie down comfortably and listen to a tape that first brought us into complete relaxation and then started suggesting that we were on a grassy hill... on the grassy hill there was a shed... who do you see standing in front of that shed? Making us imagine the journey ourselves but once in a while guiding us further on.

What is that called with an english word? I would at first think it was called "Guided meditation" but that isn't quite what the above is, is it?

I'm really interested in looking into the deeper kind, even the type that is on the verge on being dangerous, because it to my rememberance opens a lot of doors into yourself.

Thx in advance guys...