metropolis vs Cedar Rapids

metropolis and Cedar Rapids both are nouns.

Word	Noun	Adjective	Verb	Adverb
metropolis	Yes	No	No	No
Cedar Rapids	Yes	No	No	No

metropolis (noun)	Cedar Rapids (noun)
people living in a large densely populated municipality	a city in eastern Iowa
a large and densely populated urban area; may include several independent administrative districts