Robert Ballard was an oceanographer who hoped to discover the famous wreck, but couldn't get funding for his underwater exploration vehicle. To his surprise, the Navy told him they would fund an expedition, but that the hunt for the Titanic would just be a cover story for investigating the sunken subs. Kind of a good news / bad news situation there.
Ballard kept begging to have a quick real look for the Titanic until the Navy finally got tired of the whining and said he could have any leftover time if the mission wrapped up early. Since the subs weren't leaking any nuclear material, the Navy ended up giving Ballard 12 days to look for Leonardo DiCaprio's corpse, probably figuring that it wouldn't be enough to cover a vast area of the ocean. But he did it. He actually found the Titanic.
To the Navy's complete horror, Ballard became an instant celebrity and the media became very interested in the details of this "totally not looking for nuclear subs" expedition. The military managed to keep the story classified until 2017 (though some details had leaked by the late '90s). We wouldn't be surprised if they gave James Cameron $200 million just to make a movie that would throw everyone off the scent.