Gems cut out of the rock one cannot visit slovenia without visiting postojna cave the largest karst cave in slovenia with as much as 24 km of fantastic grid of tunnels galleries and halls starting with electric train taking you inside like no where else in the world then proceed for a walking tour not only england but slovenia too has its own robin hood erazem of predjama castle was a headstrong and rebellious robber baron who stole from the rich to give to the poor visit impregnable