The Tomb of Darth Vader was a burial place prepared in the Great Temple on the Sith world of Korriban to hold the remains of Darth Vader.
The tomb was never used for its original purpose. Anakin Skywalker renounced the dark side of the Force and the title of Darth Vader in the final moments of his life as he destroyed the Emperor to fulfill the ancient Jedi prophecy. Having died embracing the light side of the Force, his body became one with the Force, and his son Luke Skywalker cremated his empty armor on Endor a short time later.
Seven years later, the ancient Dark Lord of the Sith offered Darth Vader's vacant tomb to the reborn Dark Lord of the Sith and Galactic Emperor Darth Sidious, whose store of clone bodies were rapidly deteriorating. Sidious declined the offer as he intended to rule the galaxy for all eternity.