Skip the DIY headache and book the combo ticket covering Predjama Castle. The underground train ride is genuinely surreal, and spotting the blind olms in the aquarium section is the main event. Bring a hoodie because it hits a brisk 10 degrees Celsius inside year-round. It gets crowded, so book the first morning time slot to avoid the swarm of tour buses. Spend about three hours here; don't bother buying the overpriced snacks at the gate.
