Mars City

Mars City was an Autobot base from the Energon portion of the Unicron Trilogy continuity family.

Mars City was an enormous structure designed as an energon mining installation. It also served as one of many bases for the Autobots. Located in an unknown area on the planet Mars, it had a space bridge built in to it and had many Transformers based there.

Fiction

Energon cartoon

Mars City was among the targets under attack by Terrorcon raiders early in the Energon conflict. Several attempts were made to continue operations there by the Autobots and their allies, but these were largely abandoned by the time Earth's energon grid came online.