Evolution tiers
A medium sized ship approached the Shelter on planet Humding. Usually Shelters would be built on flat ground, in a square type shape with walls on all sides. Soldiers, Mechs or Travellers would be stationed on top of them to protect those inside.
On the other hand, this planet's Shelter had been built on top of a large hill, or more accurately the main base was located there. There were several large tubes that had vehicles passing through them.
These would descend down the hill into different areas that had small bases of buildings and people around them. Shockingly there were no walls surrounding them like the main Shelter at the top of the hill, instead there were people protecting the entrance to these large tubes.