"The" is an article that is used the same way with "a/an". An article works like an adjective as it also modifies nouns.
"The" is used to modify a particular or specific noun.
1.) the Amitabh Bachchans ; the Shah Rukh Khans. The use of "the" in the above phrase refers to a specific group of people.
2) the Madhubala ; specifically modifies Madhuri Dixit
3) the story, the Alexanders, the Napoleons, the Hitlers - specific type of people or people who share the same attributes or characteristics with Alexander, Napoleon, and Hitler.