Ready to have your movie-going-mind blown? What if Jack Dawson and Jay Gatsby were the same person? Sure, both characters are played by the same actor, Leonardo DiCaprio, but is the "Titanic" character and "The Great Gatsby" character in fact one in the same?
Could Dawson just be a younger Gatsby?
If you actually watched "Titanic," which if you didn't you're not an American, you would know that Jack dies in one of the most unforgettable scenes of all time (spoiler alter!) "I'll never let go, Jack!"
Obviously Rose, aka the bitch, lets go, sending Jack down to the depths of the Pacific Ocean, therefore making it impossible for him to later become Jay Gatsby.
But hey, maybe he had a snorkel and escaped to a nearby rescue boat? We can always dream.