According to the map Flint finds in the safe, Galaxy Island is in the Mediterranean Sea, almost equidistant - 250 kilometers - from the island of Mallorca, the cities of Barcelona and Marseille, and the islands of Corsica and Sardinia. In real life there is no island at that location (see also Goofs).
Average Shot Length = ~5.8 seconds. Median Shot Length = ~5.5 seconds.
Look closely when Gruber shoots at Flint, you can see that Flint starts the fight by throwing liquid soap backwards at Gruber.
On the official studio soundtrack album, the song 'Galaxy a Go-Go' was written by a young Randy Newman, who was in fact the nephew of Alfred Newman, the head of 20th Century-Fox's Music Department at that time.
The odd, discordant guitar part played throughout the movie, which is used almost note for note nearly 20 years later by an up and coming band, is a testament to the enduring quality of the composer's music. The band, Wall of Voodoo, best known for its early 1980s hit "Mexican Radio", uses that strange note progression in its updated remake of the Johnny Cash hit, "Ring of Fire." Their version, however, is a nearly ten-minute-long experiment in what would later be termed as techno music. Its mechanical programmed background rhythm and synth-heavy adaption paved the way for later bands. But its use of the riff from this film performed nearly musically verbatim, that makes their version so intriguing.
When Flint travels to France, the overhead shot as the plane supposedly approaches is indeed Marseille, more specifically le Vieux-Port de Marseille (the Old Port of Marseille), seen from the east.
When the girl is kidnapped from the shower, look to the left. Instead of "His" and "Hers" towels, there are two "Hers"