This is the 7123rd most frequent Polish word.
indonezją
"Indonezją" is the instrumental case of "Indonezja," meaning "Indonesia" in Polish.
In this sentence, 'Indonezji' is the name of the country 'Indonesia' in its locative case form to match the preposition 'do', indicating direction towards.
Podróżowałem do Azji, w tym do Indonezji.
I traveled to Asia, including Indonesia.
Here, 'o Indonezji' uses the locative case to suit the preposition 'o', denoting the topic of discussion.
Rozmawiałem dziś o Indonezji z moim przyjacielem.
I talked about Indonesia with my friend today.
In this sentence, 'Indonezji' is in the genitive case, showing possession as it modifies 'kultura' ('culture').