Re: Interesting Megastructures
Apologies posting something from a non-Hero campaign.
Last time I ran Traveller, I used a ring around a planet in synchronous orbit, with several towers connecting it to the surface. I don't have the exact figures with me, but it was "relatively" small, due to the planet's small size and rapid rotation. The ring averaged about 1km in diameter, and was somewhat underpopulated with about 90 billion people. The PC's never got around to exploring most of it, for the usual reasons....
Fortunately, the PC's were on vacation there, so the adventure didn't conclude with the destruction of the entire orbital construct. (For once. )
The real mega-structure was inside an Ancient's portal; a pocket universe containing a dyson sphere constructed around a black hole. Which of course, they destroyed. Accidentally. No, really....
XO