The first description of the Postojna Cave dates from the 17th century, when Slovenian scholar Janez Vajkard Valvasor wrote about it in his book The Glory of the Duchy of Carniola.
Pirmais Postojnas alu apraksts ir atrodams slovēņu zinātnieka Janeza Vajkarda Valvasora grāmatā Krajinas hercogistes spožums, kas datējama ar 17. gadsimtu.