Ciudad Juarez vs metropolis

Ciudad Juarez and metropolis both are nouns.

Word	Noun	Adjective	Verb	Adverb
Ciudad Juarez	Yes	No	No	No
metropolis	Yes	No	No	No

Ciudad Juarez (noun)	metropolis (noun)
a city in northern Mexico on the Rio Grande opposite El Paso	people living in a large densely populated municipality
	a large and densely populated urban area; may include several independent administrative districts