Dario Argento's Suspiria (1977) is a classic. There's simply no other way to describe it. Its use of garishly bright color, the amazing soundtrack by Argento's band Goblin, and Daria Nicoldi (Argento's wife at the time)'s fairy-tale-inspired story are groundbreaking.
By making Susie into Mater Suspiriorum, Guadagnino makes her the body politic. Susie rips open her chest and exposes her black, immortal heart. Her body, in all its lithe femininity, becomes the academy, the coven, the very perpetuation of witchcraft itself.