Great Rift Valley vs Africa

Great Rift Valley and Africa both are nouns.

Word	Noun	Adjective	Verb	Adverb
Great Rift Valley	Yes	No	No	No
Africa	Yes	No	No	No

Great Rift Valley (noun)	Africa (noun)
(geology) a depression in southwestern Asia and eastern Africa; extends from the valley of the Jordan River to Mozambique; marked by geological faults	the second largest continent; located to the south of Europe and bordered to the west by the South Atlantic and to the east by the Indian Ocean