Cyber City

Cyber City is the capital city of Cybertron. It is protected by the Autobots, whose headquarters is the building known as the Loop.

"You know our motto here at Cyber City... If we can't transform your frown into a smile, well, then we just haven't done our job!"

- a border drone

Dreamwave Armada comic
Before the great war, Hot Shot learned that the Decepticons had begun capturing Mini-Cons, and zoomed through Cyber City to tell Optimus Prime at the Loop. He broke a welcoming drone and caused some traffic accidents on the way. After collecting a bunch of Mini-Cons, Megatron entered Cyber City and declared his intention to conquer it. The Autobots resisted, but were outclassed by their Mini-Con-augmented foes and forced to retreat. The city subsequently fell in the hands of the Decepticons.

When Cybertron was attacked by Unicron a million years later, most of the Mini-Cons gathered at the Loop in order to fight him.

Energon comic
While Cyber City was in bad shape after the Decepticon occupation, it was restored to its former glory in the ten years following Unicron's defeat.