This is the 14506th most frequent Russian word.
памятниках
"Памятниках" means "monuments" (in the prepositional case).
The word 'памятниках' is in the prepositional case and specifies the physical location 'on monuments.'
На памятьниках можно увидеть интересные надписи.
You can see interesting inscriptions on monuments.
Here 'памятниках' describes the topic of discussion, 'about monuments,' using the prepositional case.
Мы говорили о памятниках старинной архитектуры.
We talked about monuments of ancient architecture.
The word 'памятниках' is in the prepositional case, indicating the context of being 'about monuments.'