The Man Who Knew Too Much
The Man Who Knew Too Much could be one of the most influential movies in history, although it may not seem like it at first.
In the first 20 minutes alone, we see an American couple whose marriage is on the rocks trying to patch things up with a bus ride through Morrocco (which showed up later in Babel) an American doctor and his wife attending a medical conference in a foreign country getting tangled up in international intrigue (which showed up later in the echt-Hitchcockian Frantic) and a hectic chase through a crowded Morroccan marketplace (which showed up later in Raiders of the Lost Ark). For good measure, Jimmy Stewart also mentions that he was stationed in Casablanca during WWII. With movies like these flooding the culture it’s amazing that Americans ever leave home at all.
(And of course the whole “assassination at the concert” sequence was lifted for the 70s Hitchcock pastiche Foul Play.)