This location is a [grim] [prison-city] that [stands as humanity's first line of defense].

The Surface

This location is a [claustrophobic] [city] where [humanity built up instead of out].

The Underworld

This location is a [collapsing] [maze] that [contains dangers and the city's infrastructure].

The Deep Roots

This location is a [hidden] [cavern system] where [the purified wellsprings are protected].