Prekmurje is the easternmost region of Slovenia bordering Hungaria. It is named after the Mura River, which separates it from the rest of Slovenia. Unlike other parts of Slovenia it originally belonged to the Kingdom of Hungary, not to Austria. This did not matter much in the Austro Hungarian Empire, but it explains the specific cultural and religious features, which differ from the rest of Slovenia.
The geologic and geographic features of this region differ also completely from the rest of Slovenia. Flatlands and hilly areas with little undreground drainage make this the actually least karstified part of Slovenia. So there are no natural caves in the area.