This is the 10375th most frequent Polish word.
cmentarzach
"On cemeteries."
Here 'cmentarzach' is used in its locative plural form to indicate the place where the action occurs, that is, 'in/on cemeteries'.
Na cmentarzach zawsze panuje cisza.
There is always silence in cemeteries.
In this example, 'cmentarzach' denotes the plural locative case as the sentence specifies an activity related to several places, 'cemeteries'.
Widziałem piękne pomniki na różnych cmentarzach.
I saw beautiful tombstones in various cemeteries.
The word 'cmentarzach' is again used in its plural locative form referring to the locations of the memories the sentence talks about, being 'in cemeteries'.