The Impregnable was a fortress located on the planet Amaltanna. Baron Edi Wedd of the Confederacy of Independent Systems used it as his stronghold during the Battle of Amaltanna, a battle of the Clone Wars. Jedi Knight Bultar Swan was the lone survivor of the battle, and infiltrated the fortress in a search for Wedd. Unable to enter his command chamber, she used her lightsaber to short-circuit the room's door-opening mechanism, sealing Wedd inside of his tomb.