I believe it was in ROTJ but I could be mistaken. Darth Vader mentions the planet Sullust. " What of the rebel fleets massing near sullust?" or something like that. In the nintendo 64 game rougue squadron you engage in a "raid on sullust." It's like a rocky lava world, with bursts of lava bubling all around, very cool. It gives a description of the planet and mission in the hand book "In this mission, you'll fly through the thick, hot, dark clouds over Sullust, a bleak, volcanic planet in the Sullust system. With the planet's surface shrouded in toxic gases, the millions of native Sullustans have created a large underground network of caves and cities. These beautiful sub-surface sites are popular tourist attractions. Sullustans are friendly, outgoing creatures with jowls, mouse-like ears, and large round eyes, who are prized as navigators, since they never forget a path they've traveled." I realize that you shouldn't look to EU for information, but since the planet Sullust is actually spoken in the classic trilogy i found it to be interesting. When you think about it, a lava type location is the only thing george lucas really hasn't done. He's said that he likes to have at least three very diferent geographical locations in each movie. So we've seen desert, space, aboard the death star, snow, swamp, cloud city, forest, the gungan city/ kamino for water areas, naboo the city, geonosis type rock planet, there really isn't anything left but a molten type planet. I think we will see a fight near lava, whether it be on the planet Sullust or in the core of courscant. EDIT: Nien Nunb is actually a Sullustan. I just read it at the official site.