I was once an extra,  A background actor or extra is a performer in a film, television show, stage, musical, opera or ballet production
Oh yes, I have heard of that before. It sounds like a fun job to do, Ive thought about it before. What do you get paid for that?
Not so much.    War films and epic films often employ background actors in large numbers
Oh man really? It seems like it would be long hours so I was hoping they get paid a lot. Do you mean movies like Star Wars? Or do you mean movies like... American Sniper?
American Sniper is one, but The stories may be fiction, historical drama, or biographical.
What are some examples of other movies you can think of that have alot of extras in them? 
grand opera musicals can involve many background actors appearing in spectacular productions.
Hmm... I don't watch many of those