Here's why:
* Noun Phrase: It is a group of words that act as a single noun. "Great Migration" refers to a specific historical event.
* Proper Noun: It names a specific person, place, or thing. In this case, "Great Migration" refers to the mass movement of African Americans from the rural South to the urban North in the early 20th century.
Example:
* "The Great Migration was a significant turning point in American history."
In this sentence, "Great Migration" is the subject of the sentence and functions as a noun phrase acting as a proper noun.