Subterranean Cities provide safe, clean and affordable housing for your colonists, with the added benefit of being sealed from harsh atmospheric and planetary surface conditions. It is much more difficult for alien flora and fauna to invade a City than open encampments, reducing colonial attrition as a result. Cities are manned by 1 Population unit, and provide housing for 100 additional Population.
1 per 100 population for maximum possible benefit
2,500 Advanced Construction Materials
Nothing
Nothing
3rd Generation Civil Engineering
Advanced Construction Materials
Content contributed by Raven Zachary.