Taxi Driver
In Martin Scorsese's critically acclaimed Taxi Driver, Robert De Niro plays Travis Bickle, a disturbed insomniac who makes a living as a cabbie in New York City. Unable to sleep, Bickle haunts the streets, increasingly obsessed with cleaning up the city. De Niro's performance is considered a tour-de-force, effectively painting the picture of a deranged man who believes it is his duty to save the world.