Phraseological units, characterised by their opaque meaning, are the subject of multiple theoretical works. The following article adds to this discussion by providing another interesting example. It analyses the case of the Arabic phraseological unit ‘open sesame’ from the “Ali Baba and the Forty Thievesˮ folk tale, permeating into French, Italian, Polish, Turkish and Japanese – languages distant both linguistically and culturally. In each of the analysed languages, we can find the so-called absolute equivalents of the unit in question. Their analysis shows how a phraseological unit of a meaning rooted in a foreign culture enters a language that initially did not connote sesame with a ‘treasury’. Interestingly, the analysed unit became understandable enough to be re-used in other cultural sources, such as names of public places, or even to enter the target language dictionaries. However, as the corpus analysis suggests, the popularity of the unit in question varies between languages, being the most popular in Italian and the least in Japanese.