The Star Wars crawl.
George Lucas had long wanted a "creeping title" (common to a lot of sci fi serials in the 1930s and 1940s), but wanted one that receded pyramidally into the background. The pyramidal crawl would echo the visuals which would come moments later.
In fact, there's a bit of a legend about the attempt to animate the crawl, only to have it fail miserably. So a physical effect was used.
Theoretically, the crawl was easy: The team used a VistaVision camera with a tilting lens (to fix focus problems), set the text almost parallel to the ground, and filmed it by running the camera up and down the text. The artwork itself is either one foot wide and four feet long (according to Ken Ralston), or two feet wide and six feet long (according to Dennis Muren). It uses up 2,000 frames of film.
The problems? The slightest blemish on the text or black background stood out like a big zit on a high school boy's forehead on the night of the prom. Glare was a huge issue. The slightest bump or movement in the camera ruined the shot. And the shot had to be lined up PERFECTLY; if the camera did not move up the text right down the middle, the pyramid effect slid off right or left dramatically.
The crew spent two weeks doing test-runs and ensuring that the dolly and the text were perfectly clean. Actual filming took three days!
FYI: Star Wars, The Empire Strikes Back, and The Return of the Jedi used Univers Light Ultra Condensed for the titles of the films and "episode number", while bolded News Gothic was used for the text. For the re-releases of these three, an altered version of News Gothic was used for the titles, and bolded News Gothic for the "episode number" and the main text.
CGI was not used for the crawl until The Phantom Menace. All subsequent crawls have used CGI. Interestingly, no notes had been kept in the 1970s and 1980s regarding font, font size, etc., so the CGI artists had to recreate everything by hand.