Underneath the surface of Daleem is a complex and extensive planet-wide interconnected tunnel system. These tunnels connect to various ancient ruins from a multitude of long dead civilizations; some even run beneath the planet’s shallow oceans. While openings to the tunnels are a rare find, it is almost a guarantee that somewhere within each surface ruin site is a way to enter the tunnels, usually through an ancient, protected hatch or a prior cave-in.

The tunnels are decidedly sentient-made and look to be in relative repair with a few exceptions. Of note, water has found its way into some sections that are under the shallow oceans, droplets dripping onto the floor and trickling down the walls. Curiously, these small pools stay relatively small even though no obvious escape route exists, causing many to believe that animals have found their way into the underground passage as well. Some travellers have even heard the skittering insects from the darker recesses of the tunnels. In addition, acrid smoke wafts and weaves through the chambers. Though harmless, the overpowering stench irritates the noses of those forced to pass through without respiratory protection.

Several data screens hang from the walls, displaying cryptic information from some unknown system. Hexagonal in shape, the long corridors are broken up by smaller indentations that appear to be blast door housings. Various conduits hang down from broken panels, and occasionally crackle and spark with electricity. At the end of each section of tunnel, between each 'door', lies a circular portal covered with hardened duraplate. Whatever lies beyond them is a mystery that has yet to be solved.