A concept of a fortified terraforming colony. Surrounded by a strong wall, entrance is only granted through the four Outer Towers. A controlled river of water acts as water filtration, irrigation for plant life being grown outside the Greenhouse, and a Moat against would-be invaders who made it over the main outer wall. The Greenhouse provides food, air, and a natural environment for the terraformers.
The design is sturdy, stout, and expandable, so it can be built on as large or small a scale as desired, and will hold up in tough weather or seismic activity. Solar panels, radar, communication devices, and defense systems can be placed anywhere on the structure.