I remember "live" projections of a TV video signal used in BBC programmes in late seventies, where you see on the stage a huge screen and seemed that it's not a film projection, and at that time I just couldn't imagine how they managed to do that, knowing only how the CRTs worked -- and big projections simply "didn't fit" that model. I considered that a pure magic.

And now searching the internet, they really did have this technology (see the comments):

https://hackaday.com/2016/03/15/retrotechtacular-eidophor-an...

"When I worked at the BBC West London studios in the 70’s we regularly used Eidophors for back projection"