concrete jungle vs urban center

concrete jungle and urban center both are nouns.

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

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