urban center vs concrete jungle

urban center and concrete jungle both are nouns.

Word	Noun	Adjective	Verb	Adverb
urban center	Yes	No	No	No
concrete jungle	Yes	No	No	No

urban center (noun)	concrete jungle (noun)
a large and densely populated urban area; may include several independent administrative districts	an area in a city with large modern buildings that is perceived as dangerous and unpleasant