This is a sapient alien species which once had a prosperous civilization, but which has been in gradual technological decay since a nuclear war that happened countless generations ago. They have at the same time, however, developed as a peaceful and reasonable culture, although utterly lacking in ambition.
Members of this species are physically huge, about ten times taller than a Human being, and possess six legs, eyestalks and pseudopods. Their planet is less dense than Earth and thus rich in lighter elements. When they feel sad they produce yellowish crystals in their eyes, which are the equivalent of humanoid tears.
- Youth, by Isaac Asimov (1952)