metropolis vs Sioux Falls

metropolis and Sioux Falls both are nouns.

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

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