Another place that we visited was the Skocjan caves. There are two famous caves in Slovenia, the Skocjan caves and the Postojna caves. The latter one is much more expensive than the Skocjan caves, so we went for the cheaper option. The Skocjan caves is really huge (it can probably fit an underground city) but the walk was really fast and it was all over in like 1.5 hours.
Taken from the web since no photos in the cave
On the way back we stopover at Predjama castle just to take a photo of this cool, in the rock building.
Oh and five days is kinda too long to spend in Slovenia. I think that 3-4 days would be a much better duration.