Titanic was released to theaters on December 19, 1997. It went on to become the highest-grossing film of all time…which nobody saw coming.

• Titanic was originally set for release in July 1997, but as the date approached, Paramount Pictures pushed it back to Christmas 1997. The movie, which cost $200 million to make, was very over-budget and director James Cameron was taking too long to make it. In fact, show business pundits widely predicted that Titanic would be a big-budget, waterlogged box-office bomb, like Kevin Costner’s 1995 movie Waterworld. (To say the least, it wasn’t. It earned $600 million, at the time the top-grossing movie ever.)

• Movies longer than three hours were considered “not commercial” by movie executives in the 1990s. Result: When Titanic was distributed to theaters, its three-hour-plus running time was listed as “2 hours and 74 minutes.”

• Nowadays films almost always score their biggest weekend at the box office right out of the gate. (Jurassic World made a whopping $200 million in its first weekend, for example.) Titanic was a slow build. In its first weekend it made $28 million, barely edging out Tomorrow Never Dies. But Titanic still holds the record for highest grossing 10th, 11th, and 12th weekends, and spent a total of 15 weeks at #1.

• Titanic spent more time at #1 than most movies play in theaters. It played regularly in American theaters until the following summer—it was the first major film to come out on home video while it was still in first-run theaters. At one point, Paramount had to send out new prints of the movie because theaters had worn out their reels.

• Matthew McConaughey, Gwyneth Paltrow, and Reba McEntire were up for the parts of Jack, Rose, and Molly Brown, respectively. The roles ultimately went to Leonardo DiCaprio, Kate Winslet, and Kathy Bates.

• It would’ve been to make a sequel to a movie about a real-life event that ends in tragedy, but a parody sequel was rushed into production in early 1998. Called Titanic Too: It Missed the Iceberg, the comedy was set to star David Hasselhoff, Leslie Nielsen, and Priscilla Presley, but it was never completed.