Rose Garden of Eternity

The  was a rose garden on the planet Tellus IV kept secret by the Gardener.

It bloomed once every thousand years and showed a prophecy written in its flowers. Its Thirteenth Flowering depicted a blue TARDIS, the Galactic Seed Vault and the number 13, which prompted Willow to ask the Thirteenth Doctor for help. (PROSE: The Secret in Vault 13)