6. Citizen Kane (1941)
Another film fit to bursting with groundbreaking developments in cinema history, Orson Welles masterpiece has inspired scores of books outlining in minute detail why it deserves to have been the BFIs greatest film of all-time for so long (before being toppled by Vertigo last year). But for the benefit of this list, one particular shot stands out as revolutionary in terms of having a huge stylistic impact on cinema: cinematographer Gregg Tolands exceptional storm-lit crane shot through the El Rancho sign and down through a skylight into a night club below. Filmmakers today can create a shot like this, with relative ease, but back in 1940 it required an extraordinarily complex array of mechanical and matte cheats to achieve. The fact that it simply hadnt been done before in quite this way, and yet has been emulated ever since, is more than enough to put it on this list.