The site of the principal Rebel base is the fourth moon of the gas giant Yavin, located in the Sumitra Sector. The lush jungles of Yavin Four become a new home to weary Rebel soldiers on the run from the Emperor's forces.
Steamy foliage and rain-forests cover the moon's surface, providing ample sensor distortion and visual cover from surveillance. These qualities and the planet's remote location make it an ideal hiding place for the Alliance. The Rebels have built Massassi Base into several abandoned temples and other ancient structures, converting them to operations wings, hangar bays and barracks. From this secret sanctuary the small Rebel force of X-wing and Y-wing fighters lifts off to attack the approaching Death Star.
Established on the moon Yavin 4 after the Rebels evacuated
their base on Dantooine, the secret headquarters of the Alliance
occupies several ancient Massassi ruins. The primary location is
the round Great Temple, where the Alliance has an enormous War
Room on the ground level, along with a Communications Center and
many common rooms built into the ancient chambers.
The top of the temple houses an observation deck, and below that is the grand audience chamber. Under the chamber are housing levels for Alliance troops. Under the command of General Jan Dodonna, Alliance engineers cleared out the ancient structures and made them fit for habitation once more, and also erected high lookout towers. The structure's lower levels provide a secure hiding place for the Alliance's precious fleet of X-wing and Y-wing fighters.