Footage of the real wreck of the Titanic, filmed from a submersible craft, was used in the 1997 movie
James Cameron's blockbuster smash-hit film Titanic told the heartbreaking story of two lovers who find themselves on the fateful maiden voyage of the 'unsinkable' Titanic, which sank after striking an iceberg in 1912, with 1,500 passengers dying in the Atlantic Ocean.
The film has come back into the public imagination following the tragic deaths of five people on the submersible Titan, which had embarked on a mission to view the Titanic wreckage.
Rescuers now believe that the vessel imploded on its decent to the wreck, causing the immediate death of all those on board. Following the news of the tragedy, Cameron spoke out about safety concerns for deep-water exploration missions, and accused OceanGate of cutting corners.
Cameron is something of an expert when it comes to these extreme tourist trips, having visited the wreck several times himself.
Part of the movie was actually filmed on location at the bottom of the Atlantic Ocean where the wreck of the 'unsinkable' ship rests.
James Cameron travelled to the wreck in a Russian Mir submersible 12 times to film footage that was eventually used at the start of the blockbuster movie.
The majority of the film was not shot on the Atlantic however, as the practical issues involved would have been insurmountable. Instead, the bulk of the action was shot on a series of huge soundstages in Baja California, Mexico - one of the sets has a water tank filled with 17 million gallons of water - it has since been used for other ocean-set movies including Pearl Harbor, and Master and Commander: The Far Side of the World.
Two real ships also served as sets for the movie - the SS Jeremiah O'Brien, a US cargo ship that was present at the D-Day Landings, was used as a stand-in for the Titanic's engine room. The S.S. Lane Victory, another Second World War era American cargo ship, was used for scenes of the Titanic's wake.
Other filming locations included an olympic sized swimming pool in Long Beach, California, and Halifax and Vancouver in Canada.
A scale replica of the Titanic was built for the movie, although it was still huge, at 85-90% the size of the real ship. So it's probably not surprising that the replica cost $40 million (the actual Titanic cost roughly $7.5 million to build - around $120 million in 1997 money).
The replica was broken into two main pieces as the actual Titanic split in half as it sank. The bow of the ship was designed to sink into the huge water tank.
Despite the vast sums spent on the film, the budget rose from $110 million to $295 million, the film was a monumental success, making $2.25 billion, and was the highest grossing film of all time until 2009, when another James Cameron project, Avatar, overtook it.
We already know that the scenes of the Titanic's sinking were shot on huge water tank sets - but Cameron had much more than this to consider.
Some sets were suspended above the tank, with footage combined with other smaller models and computer imagery to make the shots of passengers falling from into the water.
And filming scenes which require actors to be soaking wet for hours at a time carries its own risks - although the tank was heated so the water was around 26 degrees.
The film's star Kate Winslet claimed that she suffered hypothermia and the flu whilst shooting the movie - and at one point nearly drowned when her coat got coat on a part of the set. Co-star Leonardo DiCaprio fared better, his only notable injury was hurting his shoulder in a scene where he tries to ram a bench through a gate.