Orthanc

Orthanc appears in The Lord of the Rings.

Orthanc, the unassailable black tower of the wizard Saruman atop Isengard, stands as a symbol of his burgeoning tyranny in The Two Towers, evolving from a bastion of arcane knowledge into a fortified stronghold of industrial war machinery. Amid the Ents' wrathful assault, it endures as the sole remnant of Saruman's dominion, its impregnable nature underscored when the Ents fail to breach its walls. Ultimately, Orthanc becomes a prison for the defeated Saruman and a repository for the palantír, marking its transition from power center to guarded relic by series' end.