a. WWII/Holocaust:

The Pianist; Schindler's List; Life is Beautiful, The Diary of Anne Frank, Farewell to Manzanar, Judgment at Nuremberg, The Longest Day, etc.

 b. Slavery:

Amistad, Roots, Beloved, Mandingo, etc.

c. Civil Rights, Diversity, and/or tolerance movies:

The Long Walk Home, Rosa Parks,  Four Little Girls, Conrack, Gandhi, Ghosts of Mississippi, Guess Who's Coming to Dinner, The Jackie Robinson Story, A Raisin in the Sun, Sarafina, Stand and Deliver, etc.

d. Other

Ask me if you have an idea and want approval (there are many others, these are just the ones I could think of...)