Overview
An alien race called Gauna has destroyed Earth. leaving humanity struggling to survive aboard the spaceship Sidonia. Even though it’s been a century since the last encounter with the Gauna, military service is mandatory. For Nagate Tanikaze, whose grandfather secretly hid him in the forgotten bowels of Sidonia, it’s a strange new world as he’s forced to come to the surface. Yet his recruitment comes just in time, for the Gauna have suddenly reappeared.
Reviews
Not a "good" anime, but it might still be worth watching it.
Personally, if this makes any sense, I mostly did not really like it, but at the same time I did not regret having watched it. (watched so far season 1 & 2)