Stone of Scone
From Tardis Wiki, the free Doctor Who reference
The Stone of Scone is a stone block which was used for centuries in the coronation of the monarchs of Scotland, England, and Britain.
On 25th December 1950, the Doctor, Ian Chesterton and Barbara Wright took the stone from Westminster Abbey to the Doctor's TARDIS in Kilmartin, Scotland. The Doctor had seen a photograph of the stone and recognised it as a psychic life form native to Micah, and believed that it would be safer in the TARDIS. In April 1951, they moved a replica of the stone the Doctor had created to Arbroath Abbey, but it was accidentally dropped and broken in two. A group of Scottish nationalists took the blame for the theft, and the Doctor kept the real stone in his TARDIS, where it was content. (ST: Set in Stone)
