The Fal-lan-tral was a location on Vulcan. Known as the Passage of All Mysteries, it was located near Mount Seleya. The area consisted of a worn path that was paved with ancient blocks of a dusty red stone which led up to the opening of a cave by the mountain's side. A labyrinth of hand carved tunnels were inside with passageways which only Vulcan's had seen and was where the Tral Katra were located.
In 2373, Spock arrived at the Fal-lan-tral in order to make peace with his deceased father's Sarek katra. (TOS novel: Avenger)