10 pages

Here are some possible topics :

A transformation in American Cinema; for example, the development of the Classical Hollywood Studio System;

 From SIlent to Sound; 

Screwball Comedies and the Zany Sound Comedies of W.C. Fields, The Marx Brothers, The Three Stooges, Bob Hope, and others.

Censorship and the Pre-Code Era, the Catholic intervention in censorship from 1934 to 1965; the Movie Rating System, from effectively 1966 through the present.

The Cold War Era and HUAC and the Blacklist.

WWII Propaganda Films (see the folder called Five Came Back and the films associated with Mark Harris's book;

Genre development, starting from the early Westerns and Melodramas; Comedy's Greatest Era; The Musicals from 1927 through the Golden Age, into the 1960s; Films Noir (1940-1950s, although they continued longer.

The Blockbuster Mentality (1975 to present; although I consider The Godfather from 1972 as the beginning).

Black Hollywood: From Oscar Micheaux and Paul Robeson to today.  The Golden Era of Black Filmmakers and Films started in the 1960s, and has never truly been acknowledged.

The Social Problem Film, which has always been present and could be considered a genre.  I'll be naming some of these in my list for BB as they began in the early 20th century (Children Who Labor, e.g.).

You can also write about a director, cinematographer, actor, screenwriter, and other artists who have made American Cinema the most popular in the world.  

You can write about one film or as stated above, a few films to illustrate a genre.