The Citadel Var'Theldun was a structure located on the planet Romulus.

It was the third most important building in the capital of Val'danadex Trel; behind both the Imperial Romulan Senate and the Praetor's Palace. The Citadel was the home and headquarters of the feared Romulan intelligence service; the Tal Shiar. Many tended to avoid this structure with some even going as far as trying to prevent the shadow of the building from touching them in the belief that it would mean imprisonment within its walls. Those that enter the Citadel were doomed to never appear in the streets of the capital again and instead suffer a life on a far off penal colony in the Romulan Star Empire. (Last Unicorn RPG module: The Way of D'era: The Romulan Star Empire)

the planet Romulus
cities and settlements	Avra Trel • Bareldak Trel • Calanista • Caranam • Ch'eren • Chaladra • Dinalla • Dorvek • D'Sivas • East Umrika • Gavros Trel • Hlarek • Ihhlaie • I'Ramnau • Kanassarum • Kar'Mael • Ki Baratan (Government Quarter) • Kromtal Trel • Leinarrh • M'Narth • Portora • Rateg • Ra'tleihfi • Rhehiv'je • Tal K'shir • Tephren • Torven • Vela'Setora • Villera'trel
landmarks and institutions	Aekhhwi'rhoi • Arena of Life • Astrophysical Academy • Avenue of Processions • Boulevard of Heroes • Citadel Var'Theldun • Colleges of the Great Art • Hall of Columns • Hall of State • Imperial Academy of Arts • Imperial Palace • Square of Heroes • Plaza of the Endless Sky • Victory Square • Vikr'l Prison
nations and provinces	Elheu District • Kihai * Tikal
geography	Allerash Mountains • Ar'hael Desert • Beld'Rath Peninsula • Cave of Winds • Firefalls of Gal'Gathong • H'aareld va Groth'Chok • Hallows • Jeweled Forest of Ath'reshaar • Kae'raktar Mountains • Kor Thon • Landrosh Mountains • Plains of Aihai • Raas'trek Mountains • Sen'lanark Mountains • T'aresh Mountains • Valley of Chula • Valley of Fire • Wall of Fire Mountains
continents and landmasses	Brel'Kar • Dektenb • Ehrie'fvil • Masfarik • Novok • Umrika • Sath'har Archipelago • Uulma Islands • Umrika • Valkarja
bodies of water	Apnex Sea • Balsanra River • Bareldak Bay • D'Gansar River • Dorvek River • Garenah Sea • Gend'eroth River • Haverelar Sea • H'relgath River • Jendraax Strait • Sea of Lerodan • Nelrek Ocean • North Mendlanar Sea • Sherdak Sea • South Mendlanar Sea • Tai'eld River • Terelex Straits • Thal'Tharin River • Tor'ren River • Sea of Vrekess • White Sea