I recently watched Indiana Jones and the Last Crusade again and noticed a small but significant detail.
I'd noticed before that there's something of an echo between the beginning and end of the film. At the beginning, as he's copying an image from an illuminated manuscript, Dr. Jones, Sr. says, "May he who illuminated this illuminate me." (With a double meaning on illuminate, which is where I got the name of this blog.) At the end, when the adventure is all but over, Indiana Jones asks his father, "What did you find, dad?" and Dr. Jones, Sr. replies, "Illumination."
Watching the film this time, I noticed a third instance of this illumination. During the chase through the catacombs under the library and through the canals of Venice, Indiana Jones and Dr. Elsa Schneider run past a sign that reads: "Calle di S.ta Lucia."
Here are two frames (one is more legible, and one shows the characters a bit better):
"Calle di S.ta Lucia" means "St. Lucia's Lane." St. Lucia is the patron saint of sight, and her name is related to words for light (such as luce in Italian and lux in Latin). Taken with "lane," this seems to indicate that the characters are on their way - travelling along the path, as it were - to the illumination that occurs at the end of the film. Since, however, Elsa certainly doesn't find illumination and Indiana Jones doesn't answer what he's found (instead, he quibbles about being called "Junior" again), the sign actually seems to apply more to Dr. Jones, Sr. or even to the audience.