Sioux Falls vs metropolis

Sioux Falls and metropolis both are nouns.

Word	Noun	Adjective	Verb	Adverb
Sioux Falls	Yes	No	No	No
metropolis	Yes	No	No	No

Sioux Falls (noun)	metropolis (noun)
largest city in South Dakota; located in southeastern South Dakota	people living in a large densely populated municipality
	a large and densely populated urban area; may include several independent administrative districts