metropolis vs Thunder Bay

metropolis and Thunder Bay both are nouns.

Word	Noun	Adjective	Verb	Adverb
metropolis	Yes	No	No	No
Thunder Bay	Yes	No	No	No

metropolis (noun)	Thunder Bay (noun)
people living in a large densely populated municipality	a port city in Ontario on Lake Superior
a large and densely populated urban area; may include several independent administrative districts