- Reach level 19, open the Technology menu and unlock Stone Structure Set for 3 Technology points.
- Collect what you need:
- Open the Build menu (B on PC), go to the Foundations tab, then Stone, and pick Stone Pal Passage Entrance. Place it inside your base.
Stone Pal Passage Entrance
An entrance to a Pal passage built on a foundation.
Made from stone, it is reasonably sturdy.