The Fleabirds are a group of people indigenous to North America who have rejected the collectivism and sedentary lifestyle inherent in the Cosmic Era. Rather than living in the gleaming arcologies, steaming geofronts, or the great heaps of the urban rims and favelas. Rather, they live in caravans that travel the countryside of the continent.
A cave with weapons sunken into the walls, blades sticking out of the floor and ceiling, and so on. Possibly, any weapon used in it could be torn out of the hand and sink into the stone.