I had an idea for a Lego theme, where a group of adventurers discovered a lost civilization in the mountains. I thought it would be cool if this ancient civilization had developed all these advanced technologies, or some kind of metalworking technique, and that they incorporated them into caves in the mountains. The technology/metalworking could be used as protection, but I just thought it looked cool. So basically, scientists discovered ancient remnants of a cave-dwelling people, who have technologies that far out-perform the technology of today's world. I believe that there could be endless possibilities with a theme like this: The good guys want to research + protect the culture, while the bad guys want to steal it for world domination! Anything is possible really, I just wanted to focus on the "ancient people with advanced technology" part of the theme.