Senate Tier 125 was one of the many levels that constituted the main Senate Chamber of the Galactic Senate Building on the galactic capital world of Coruscant.
Tier 125 was unique, in that it contained the main control panel for the chamber's 1,024 Senate repulsorpods that were used by the Senators, their aides and guards.
In 24 BBY, before the Clone Wars, galactic criminals Granta Omega and Jenna Zan Arbor conducted a major operation against the Republic. They targeted not only hundreds of Senators, their advisors, and some Senatorial aides, but also their prime target, Supreme Chancellor Palpatine, in a massive assassination attempt in the Senate Building's Grand Convocation Chamber.
Omega's army of programmed seeker droids (hundreds strong) contained the vital information to key Senators as well as to Palpatine. Soon, the Senate chamber was "filled with shouts and screams, the smoke of blasters, and the unmistakable smell of fear." Once the attack had commenced, one member of the Jedi Order that had raced to the Senate's desperate defense—Jedi Knight Obi-Wan Kenobi—quickly realized, because of the droids' advantage of flight, that the Jedi needed an edge to even have a fighting chance in protecting the thousands of beings there, who were their stewardship. But fate seemed to smile on the Republic when Kenobi found a terrified Senatorial assistant hiding among the opulent drapery of planet Belazura's pod, still tethered to its docking point. Kenobi asked the aide where the main pod controls were. Hearing the durasteel in Obi-Wan's voice, the hesitant assistant quickly let him board, then dropped the pod 10 levels to show him the central controls for the repulsorpods (which overrode all individual-pod controls) that were set in a wall-panel on Senate Tier 125. Pushing several diagram indicators, Kenobi formed the pods in a schematic, shaping large blocs of them to take on a stepping-stone effect throughout the Senate chamber. Telling the trembling aide to remain where he was, for safety, Obi-Wan raced back to the tier entrance, where he could already see he'd been successful. Able now to cover more airspace, the Jedi were jumping from pod to pod, steadily decreasing the number of droids that were zeroing in on the terrified Senators. And Jedi reinforcements from the Temple, including Shaak Ti and Coleman Trebor, were now charging out onto the Senate floor. The Jedi could see that the tide had turned.