RMS Titanic

The RMS Titanic was a luxury ocean liner on Earth in the early 20th century, noted as being the largest ship of its time. It was famously called "unsinkable," yet sank on its maiden voyage on 15 April 1912.

The Seventh Doctor, Ace and Bernice Summerfield travelled to the Titanic, tracking Huitzilin. They were on the ship when it collided with the iceberg. (PROSE: The Left-Handed Hummingbird)

El Ape, a temporary travelling companion of the Seventh Doctor, actually caused the ship to sink. (COMIC: Follow That TARDIS!)

The Master, trapped on Earth in the early 20th century, boarded the Titanic when it sank, to avoid the upcoming First World War by migrating to the United States of America. (AUDIO: Mastermind)

The Fourth Doctor had an issue of the Daily Mirror describing the disaster, which Borusa was seen to read. On noticing this, the Doctor promised that he had nothing to do with the ship's destruction. (TV: The Invasion of Time)

The Ninth Doctor persuaded several people to not board the liner on its maiden voyage. (TV: Rose) He even told Jabe that he had once been on a ship that "they said was unsinkable. I ended up clinging to an iceberg. It wasn't half cold." This seems a probable reference to his adventure on the Titanic. (TV: The End of the World)

When asked by her teacher why the Titanic sank, Mels said it was because the Doctor didn't save it and called the teacher stupid for not knowing. This got her sent to the head teacher's office. (TV: Let's Kill Hitler)

Recreation
Max Capricorn, the head of Max Capricorn Cruiseliners, constructed a starship replica of the Titanic for a voyage from Sto to Earth for the observation of "primitive cultures" on Christmas Day 2008. (TV: Voyage of the Damned)