This is the 8258th most frequent Polish word.
oświęcimiu
"Oświęcimiu" is the locative case of "Oświęcim," a town in Poland, known internationally as Auschwitz.
Here, the word 'Oświęcimiu' is used in the locative case to indicate the location where the action took place.
Byłem w Oświęcimiu w zeszłym roku.
I was in Oświęcim last year.
In this sentence, 'Oświęcimiu' is used in the locative case as part of an expression following the preposition 'o' to indicate the topic of discussion.
Czy słyszałeś o wydarzeniach w Oświęcimiu?
Have you heard about the events in Oświęcim?
Here, the name 'Oświęcimia' appears in the genitive case, reflecting its role in defining the destination in a travel context described by the phrase.