What was the name of the 1972 film whose New Year's Eve ocean-liner disaster is central to its plot?

The Poseidon Adventure is the 1972 film centered on an ocean-liner disaster occurring on New Year's Eve.

The film follows passengers aboard the fictional SS Poseidon after a massive undersea earthquake generates a tsunami that capsizes the ship. A small group of survivors attempts to reach the hull, which has become the vessel's highest accessible point. Their journey turns the familiar luxury liner into a dangerous inverted maze.

Directed by Ronald Neame, the film was based on Paul Gallico's 1969 novel of the same name. It became a major example of the 1970s disaster-film cycle and was noted for its ensemble cast and elaborate practical effects. The story's New Year's Eve setting provides an ironic contrast: the passengers begin with a formal celebration, then must survive a catastrophe while the ship is overturned. The film should not be confused with its 2005 television remake or the 2006 theatrical remake, Poseidon.