This is the 7492nd most frequent Polish word.
kołobrzeg
Kołobrzeg is a city in northwestern Poland on the Baltic Sea.
Here, "Kołobrzeg" is used as a proper noun, referring to the name of the city in Poland.
Kołobrzeg to piękne miasto nad morzem.
Kołobrzeg is a beautiful city by the sea.
In this sentence, "Kołobrzegu" is the locative case form of "Kołobrzeg," adapted due to the context of 'going to a place'.
W tym roku nasza rodzina jedzie na wakacje do Kołobrzegu.
This year our family is going on vacation to Kołobrzeg.
"Kołobrzeski" is a derivative adjective from "Kołobrzeg," describing something belonging to or associated with Kołobrzeg.