The Valley of Extinction was a dark valley on the mysterious Wellspring of Life, the world from which midi-chlorians and life itself were born. During his quest to discover the secrets of immortality, Jedi Grand Master Yoda passed through the Valley of Extinction, which displayed itself as a hallway in the Jedi Temple on Coruscant filled with the lifeless bodies of dead Jedi. It later revealed itself more idyllically, depicting a Jedi Order untouched by the horrors of the Clone Wars, which Yoda soon realized was an illusion.
- Ultimate Star Wars