Hammer Film Productions kept horror cinema alive when it was damn near dead. Universal had all but given up on the film genre that brought them so many riches in the 30s and 40s. Frankenstein and Dracula were reduced to parodies of their former selves. And then Hammer came along. This historical account of Hammer Films is superb.
I advise watching the Tubi version, because it has about an hour more content. But, if you’re pressed for time, this version on YouTube is still fun: