metropolis vs Auckland

metropolis and Auckland both are nouns.

Word	Noun	Adjective	Verb	Adverb
metropolis	Yes	No	No	No
Auckland	Yes	No	No	No

metropolis (noun)	Auckland (noun)
people living in a large densely populated municipality	the largest city and principal port of New Zealand
a large and densely populated urban area; may include several independent administrative districts