urban center vs Pompeii

urban center and Pompeii both are nouns.

Word	Noun	Adjective	Verb	Adverb
urban center	Yes	No	No	No
Pompeii	Yes	No	No	No

urban center (noun)	Pompeii (noun)
a large and densely populated urban area; may include several independent administrative districts	ancient city to the southeast of Naples that was buried by a volcanic eruption from Vesuvius