Winter Star
From Tardis Wiki, the free Doctor Who reference
The Winter Star was the location of a century-long siege by the Heroes of ancient Gallifrey. (PROSE: Cat's Cradle: Time's Crucible)
In an alternative reality in which the Doctor never left Gallifrey, the Frost Fairs of Ice Askar were but one of the many infinite possible realities he showed his granddaughter Susan in the Possibility Tree, from where one could "skate through the sky and carve sculptures in the clouds." (AUDIO: Auld Morality)