Tomb of the Uncertain Soldier

The Tomb of the Uncertain Soldier was a monument on Gallifrey that the Time Lords erected in order to contain the body of an unknown Gallifreyan. This individual existed in an alternate reality which he erased from the timeline for the greater good of the universe. His actions meant that this individual was honoured by the Time Lords, who kept the tomb on their homeworld. (PDA: The Infinity Doctors)