The release of James Cameron's Titanic in 1997 saw the film become the first to gross more than $1billion worldwide at the box office.
Its level of success was matched by the painstaking detail which went into producing the film, including the huge undertaking of creating a replica of the ship to 90 per cent scale.
Producer Jon Landau explained that the decision was made to only build one side of the ship in the tank to be used for exterior shots of the passenger liner which set sail on April 10, 1912.
The starboard side was constructed, forcing the crew to build Southampton dock on that side to film the sequence of passengers boarding the ship.
In reality it docked on the port side, meaning the shots weren't an accurate representation of how it had looked in history.
To overcome this problem, the scenes were filmed and the images were flipped - but that brought its own problems.
Every tiny detail on set also had to be reversed to look normal; text had to be written backwards, driver's steering wheels were switched the left, costumes were altered, actors swapped positions and even Kate Winslet's hat had to be lifted on the opposite side to maintain continuity.
Footage from behind the scenes shows White Star Line - Titanic's operator - to be written backwards in huge letters on the building, on worker's clothes and on the brim of their hats.
Speaking about the challenge, James Cameron said: "Let's see, if I have a scene that takes place on the port side but I only have the starboard hull then I have to shoot the scene on the starboard side and then turn the film around mirror image later.
"It gave us a little bit of a brainteaser trying to figure out exactly how to cheat these things so that they would look right.
"'Where were you standing again? Who was on your right? Okay well if they were on your right, they're going to be on your left. And you were holding hands with your right hand, oh turn your hat around'. It was a nightmare.
"It's just not something you want to do, but we saved millions not building that other side of the ship."
