Necromunda (Planet) - Forbidden Cities: The military tunnels that link the many hive cities of Necromunda run deep beneath the Ash Wastes, cut into the very bedrock of the planet. This network was constructed so that military forces could be moved quickly around the planet in the event of invasion, enabling them to be concentrated wherever needed.Access to the hives is via great ramp-shafts guarded by gatehouses, but unauthorised persons are able to gain entry through the heat sinks and air vents. Under the hives, and linked to this underground tunnel network, are cavernous storage depots and bunkers, used for stockpiles of synthetic food (in the reconstituted form of corpse-starch) and raw materials in anticipation of war or some other disaster.The tunnel system and its associated bunkers are very ancient, dating to a time before the hives had grown to the massive size they are now. As the system is continually being renovated or enlarged, many tunnels and bunkers have been bypassed or become disused and sealed up.Over the millennia, these unused tunnels and bunkers have been forgotten or lost, but since the discovery that these places are the only source of the valuable drug "spook," they have been secretly recolonised and are now known as the "Forbidden Cities."If they've heard of them at all, most Necromundans don't believe the Forbidden Cities are real, thinking their existence to be yet another urban fable.It is in these ancient bunkers that the decayed corpse-starch deposits are found which are used to make spook, and it is likely that officials of the Lord of Necromunda discovered the distinctive green deposits while supervising work on the tunnel network.Since then the nobility and the ruling dynasty of Necromunda has always had a hand in the production and trade in spook. Only the nobles, with their ability to call on the service of subordinate clans, techs and paramilitary forces, have the diverse resources needed to process the decayed corpse-starch into spook.As time creeps on, the cavernous vaults of the Forbidden Cities are extended and embellished with the wealth brought in by spook. Pillared halls are cut from the rock, and polished stones and mosaics adorn the floors, ceilings and walls. Each has become a palace of archaic, decadent splendour.The Forbidden Cities' workforce is press-ganged from the scum of the underhives, supervised and guarded by savage under city gangs. If they cannot find enough willing workers, they will incite these gangs to make slave raids into the lower hab zones or offer to buy captives from nomad slavers of the ash wastes. Once introduced to the decadent life within the Forbidden Cities, most slaves are reluctant to ever be free again.Spook exploitation brings in incredible wealth, helping to maintain the privileged life of those noble families secretly involved in its manufacture and trade. These are the so-called "Lords of the Forbidden Cities." Some are of noble origin, others are adventurers of obscure origin who have connections with the established Necromundan nobility of the Great Houses and the Clan Houses.Frequently they are members of Noble Houses who have gone into exile because they are suspected psykers or wish to escape from political enemies. They simply disappear from the upper spires, setting up court in the hidden bunkers where the spook is processed.