As more people settled into the region, the local government eventually stumbled upon a branching tunnel system leading deep into the earth. A number of other entryways into the system did exist, but they were usually too narrow to go through. This one proved to be both the safest and easiest to access, being larger than a full-grown person, and blocked off to the public. Some adults and children still managed to find their way into the tunnels, and much like the old expedition teams, they disappeared. Few escaped the intricate tunnels, but those that did tell stories of a lost and abandoned civilization underground. These were officially regarded as hallucinations from possible head trauma, or from breathing in any foreign substances found in the caves. Long after the established expedition camps were destroyed by the hordes of Mutants and Zombies pouring into the Dust Bowl, a camp full of Mutants was spotted near the tunnel entrance. Many small groups of Survivors invaded the camp trying to prevent another Mutant stronghold, but failed. As more groups of Survivors kept up the assault against the infected menace, they saw previously allied combatants change sides without turning. Fighting subsided soon after the people in their ranks spread the word that this stronghold was different - that the Mutants inside were peaceful and meant no harm to the survivors of the wasteland.