c. 3,996 BBY
27 ABY (later rebuilt)
The Senate Building, sometimes known as the Senate Rotunda, Convocation Center, or Senate Dome, was the building on Coruscant which served as the seat of the Galactic Senate at the end of the Old Republic. The designers claimed that any weapon capable of destroying the Chamber would also have to be powerful enough to destroy the entire planet, making the facility invulnerable against sabotage or orbital bombardment. It was also considered the New Republic's most famous symbol of freedom.
A massive building boasting a diameter of more than two kilometers and several hundred meters tall, with a shield-shaped dome mounted on a narrower drum-shaped body, the Senate Rotunda was built some time after the duel in the old Senate Hall due to insufficient security.
Located in the heart of the Senate District, the building was situated at the end of a large, flat concourse known as the Avenue of the Core Founders. This area was lined with tall, thin humanoid statues, each representing a founder from each of the habitable Core worlds. At the end of the concourse was one of the ceremonial entrances, the Great Door. It was adorned with the Great Seal of the Republic and the sigils of the Thousand Worlds, which were members of the Senate. Directly inside the Great Door was the Atrium of the Senate. This was a grand entry hall, that was lined with statues of the Republic's greatest heroes and politicians.
The majority of the building was dedicated to the Grand Convocation Chamber, a large round room over a hundred meters tall, filled with floating repulsorpods and dominated in the center by a podium used by the Supreme Chancellor, the Vice Chair and the Senior Administrative Aide to coordinate the sessions. The chamber contained a total of 1024 repulsor pods, one for each Senator. When a Senator wanted to speak, their pod would detach from the wall and move towards the center of the chamber so that all the Senators could see it.
Underneath the Grand Convocation Chamber was the Chancellor's holding office, which was a preparations area used by the Chancellor to prepare to address the Senate and entertain guests. When not in use, the Supreme Chancellor's Podium would rest in this space. When he wished to address the Senate when it was in session, the podium, mounted on a large hydraulic pillar, would rise up through the retractable ceiling of the office and into the Senate Chambers. The Podium contained controls that were used to coordinate the movement of the Senate's repulsorpods. The Chamber was ringed with the Grand Concourse, where the Senate Guards stood guard at every repulsorpod entrance to protect the Senators seated there.
Many mall enhancements were made inside the chamber to increase the comfort of the Senators in attendance. On the ceiling of the chamber, large viewscreens were installed to allow the congregation to view up close visuals of the being speaking. Because sessions tended to grow long and last into the night, natural light and air was not used to fill the room. Instead, an artificial glow kept the room lit so as to diminish the senators' sense of time.
Accessed by the Grand Concourse were the offices of each senatorial delegation. Each delegation was given large amounts of office banks that could be customized to more closely resemble the native environment of the specific Senator's home planet. The Senate's communications were handled by the Senate Communications Center. The building itself was protected by an automated defense perimeter.
Built circa 3,996 BBY after the Great Sith War, the Senate building was used up through the end of the New Republic as the seat of the Galactic government. Built around the remains of the old Senate Hall, the new mushroom-shaped building was one of many prominent sites on the city-planet. In the halls of this building, many great issues were decided upon including: the passage of the Ruusan Reformation, the funding for the additions to the Jedi Temple, and planetary admissions into the Republic.
After the Vote of No Confidence in Chancellor Finis Valorum was accepted, Palpatine became Chancellor. Through his term, the Clone Wars began sending the Senate into turmoil as more and more of the Republics member planets withdrew. At the end of the war, Palpatine dueled Jedi Grand Master Yoda in the senate building, destroying a great many number of the repulsorpods. After its restoration the newly dubbed Imperial Senate used the chambers until the body was dissolved. The building would stand as an emblem of what once was, along with the Jedi Temple.
The Senate Building survived the Galactic Civil War largely intact, although not without some wear and tear. It was the first structure to be rebuilt after Imperial factions turned Imperial City into a warzone. Plans were being put in motion to overhaul the building in 17 ABY when the venerable structure was severely damaged by a terrorist bomb, necessitating a major rebuilding.
The subsequent reconstruction saw the internal fittings of the auditorium completely replaced, and the Grand Convocation Chamber which reopened in 19 ABY was thought of by many contemporaries as an entirely "new" structure, distinct from the old Senate Hall. The chamber was extensively redecorated, the Chief of State's podium was lowered to ground level, and most strikingly of all, in place of the former geometric arrangement of repulsorpods, the seating for delegates was organized into clusters of differing size and shape arranged around the rotunda, connected to each other by ramps and stairways, and capable of holding more than 2,000 delegates. The overall effect of the design was to create a complex arrangement of contrasting forms and details, combined nevertheless into a clear, coherent harmony.
However, the old Senate Building proved to be an exceptionally durable structure, and substantial elements of the original fabric remained in situ following the rebuilding. The main entrance was still through the venerable Great Door and the Atrium which it enclosed, and while the fittings of the Senate Chamber might have been entirely new, they had been reverently installed in an old auditorium, leaving the preexisting structure intact underneath.
After the Fall of Coruscant, the conquering Yuuzhan Vong selected the Senate building for transformation into the Well of the World Brain. Shaped like a Yuuzhan Vong skull, the metals of the Building were digested by yorik coral, going deep underground, and providing the Well with an impenetrable wall, capable of surviving concussion missiles and orbital bombardment—possibly even a planetary explosion, allowing the World Brain to survive as a self contained vessel. A hedge maze of ceremonial trees lined the front entrance to the Well. The trees were as resilient as durasteel, and contained toxin filled needles ranging in size from a thumb to a forearm.
During Jacen Solo's sham attempt to sacrifice Ganner Rhysode to the World Brain, Ganner fought off scores of Yuuzhan Vong Warriors, becoming a legend to both the Jeedai heretics and the Warrior caste alike.
During the Liberation of Coruscant, Han Solo, Leia Organa Solo, and the Priest Harrar went to the Well in an attempt to prevent the World Brain from destroying Coruscant. The Yuuzhan Vong subsequently repaired the atrium in a way that disguised the damage to the ancient structure underneath.
Following the liberation of Coruscant at the end of the Yuuzhan Vong War, the World Brain remained in situ, beneath the Senate Chamber. The Senate body had returned to the capital by 35 ABY, and launched a concerted effort to restore the building to its original state. Along with the geometric placement of the repulsorpods and the Chief of State's podium, the building was a mirror image of the building Chancellor Palpatine served in. During the Second Galactic Civil War, it was once again a center of governmental activity. The Building was still standing, at least, as of 130 ABY.
Although the Senate chamber in Traitor (28 ABY) is clearly intended to be the same space used in the prequels, references in several novels, including Specter of the Past (dated 19 ABY) and Dark Tide: Onslaught (26 ABY), suggest that the old Senate building had been irreparably damaged in the attack in The New Rebellion (17 ABY), and subsequently demolished.
While the earlier authors had obviously intended the new Senate to be a completely new building, it is possible to reconcile the novels by assuming that the new structure was in fact erected within the shell of the old Senate Building.