Citadel

Built on the planet Lola Sayu, the tower-like Citadel sat on a bridge between two yellow lava lakes and was powered by geothermal energy. The prison's structure was widely believed to be impregnable, with its front section sticking out over the lava, the back giving out to the prison's landing field, which was protected by fences and security emplacements. The outer walls of the Citadel were laced with hundreds of electromines, which, when combined with the planet's high winds, prevented infiltrations by pushing would-be infiltrators into the lava lakes below. Searchlights could pick out anyone attempting to enter or exit the prison, and every door along the outer wall was protected by a ray shield.

Within the Citadel was a labyrinth of identical hallways and corridors. Each hallway was protected by electrified walls, magnetic ceilings and floors, rapidly closing blast doors, cameras, and automatic lasers. All security equipment was monitored from the central control room located at the top of the prison tower. Outside the prison was a landing platform, which was protected by two manned turrets.

Constructed in 522 BBY, the Citadel was originally designed by the Galactic Republic to hold rogue or dark Jedi. In 520 BBY, the Citadel housed a rogue who was imprisoned there. Between 82 BBY and 68 BBY, there was a rumor circulating amongst the Jedi that the Jedi Council opened a new correctional unit at the Citadel for those that had foresight. Following this, Jedi Master Lene Kostana refused to tell the Jedi Council that the Force visions plaguing Jedi Padawan Sifo-Dyas grew worse than when then Jedi Padawan Dooku and Dyas last met in the mission to the Outer Rim planet Asusto, in fear that Dyas would be locked up at the Citadel. At some point, Kostana met with Dooku at a hangar located in the Jedi Temple on the Core Worlds planet Coruscant after Dooku had a sparring session with Jedi Rael Averross. While talking to Dooku, she told him about the rumor. Dooku did not believe the rumor but promised to not cause Dyas any "distress" over the matter. By the time of the Clone Wars, the Jedi Archives were known to have information on the original layout of the facility, but this was considered extremely old and outdated at the time.

During the Clone Wars, the citadel fell under control of the Confederacy of Independent Systems. It was run by warden Osi Sobeck who was considered to be sadistic. Under Separatist control, the Citadel became known as the Confederacy's most isolated holding facility that held high value detainees. The prison was heavily guarded by a number of droids including BX-series droid commandos, and it had hundreds of electromines. The clone trooper training facilities in Tipoca City on the extragalactic planet Kamino used a Citadel Challenge training course named after the prison.

In 20 BBY, Jedi General Even Piell and his officers were captured. Piell was then incarcerated and tortured for information regarding the Nexus Route in the Citadel, prompting the Jedi Council to send an elite rescue team led by Jedi Generals Obi-Wan Kenobi and Anakin Skywalker to free him. After the team snuck past the life-form sensors employed by the Separatist fleet guarding the planet, they landed just outside the Citadel using a stolen Sheathipede-class transport shuttle. They began to scale a steep cliff-face dotted with electromines, but when clone trooper "Charger" slipped and fell on one of the mines resulting in him dying, this alerted the Separatists of their presence. The task force nevertheless managed to infiltrate the prison and rescue Piell, Captain Wilhuff Tarkin, as well as several Clone naval officers and troopers.

When they prepared to rendezvous with the evacuation team that consisted of astromech droid R2-D2 and a group of reprogrammed Separatist battle droids, a firefight broke out on the landing pad. Republic ARC trooper CT-1409, "Echo" was presumed dead when a BX-series droid commando blew up the Republic's stolen shuttle on the platform outside the facility. During the Jedi's escape with their clone troopers across Lola Sayu's unstable terrain, a group of anoobas and droids led by Sobeck attacked them. General Piell was fatally injured by one of the anoobas, but Piell managed to whisper his half of the Nexus Route information to Jedi Padawan Ahsoka Tano before succumbing to his injuries. Sobeck was later killed by Ahsoka Tano while attempting to throw Tarkin into a lava gorge. The group managed to reach the rendezvous point where they were extracted from the planet by a Republic Low Altitude Assault Transport gunship.

After the Clone Wars, a droid led a Separatist holdout at the Citadel. However, the droid leading the garrison of battle droids malfunctioned and instead followed its last directive from the previous war. It had adjusted its programming for a wider target range and targeted all Force-sensitives. The droid eventually came to have a in the prison. This caused a where a Jedi Warrior managed to free the child. By 9 ABY, Unga Toba served a twenty-five year sentence presumably at the citadel for unlawfully accessing a computer.

The location first appeared in Star Wars: The Clone Wars third season's eighteenth episode "The Citadel" which aired on February 18, 2011. The design illustration of the Citadel was done by design and concept artist Tara Rueping. The appearance of the Citadel was meant to be visually similar to the Death Star's surface when seen from afar and the animation sequence when Jedi Masters Obi-Wan Kenobi and Even Piell emerge from the ventilation shaft was originally shot on top of the Citadel tower however it was later moved with minimal pickups to the landing area behind the tower. The monitoring devices lining the hallways of the Citadel were designed from similar looking devices aboard the DS-1 Orbital Battle Station in the movie, Star Wars: Episode IV A New Hope.