This is the 9465th most frequent Polish word.
wałbrzychu
"Wałbrzychu" is the locative case of "Wałbrzych," referring to the city of Wałbrzych in Poland when used in contexts like "in Wałbrzych" or "about Wałbrzych."
Here, 'Wałbrzychu' is used in the locative case of the noun 'Wałbrzych', indicating the location where the action occurred.
Mieszkałem w Wałbrzychu przez dwa lata.
I lived in Wałbrzych for two years.
In this sentence, 'Wałbrzychu' is again in the locative case, describing the place where the event of stopping took place.
Podczas wycieczki zatrzymaliśmy się w Wałbrzychu na zwiedzanie.
During the trip, we stopped in Wałbrzych for sightseeing.
Once more, 'Wałbrzychu' appears in the locative case, serving to specify the locality of the cultural events.