extinct interstellar civilization theme

A civilization that flourished to the extent that they colonized other planets, but then went extinct for some reason or another. What perils may the distant future hold in store?

6 total · 1 choice · 4 major · 1 minor

StoryLevelMotivation
movie: Forbidden Planet (1956) choice The Krell traveled to other worlds but then destroyed themselves.
bbf1x04 major The alien civilization on Ikarra VII civilization killed itself off as a result of having developed organic technology.
movie: Cat-Women of the Moon (1953) major The Cat-Women were the last eight survivors of a two-million-year-old civilization, and the scientific expedition explored the ruins of their ancient Moon city.
tng1x05 major Tkon :: Tkon empire
tos3x14 major The Enterprise crew discovered an artificial planet that had been created by the long gone Kaladan alien civilization.
tas1x01 minor Ancient Insectoid Species :: insectoid aliens