Located within Thunderhead itself, the Processus Megastructure is an enormous subterranean structure with little internal logic or coherence but following simple logical rules. It is composed of early organic minerals and seems to be a self-modifying structure. Through means are little understood, it has has been artificially limited to just under a 1000 kilometer radius and about as far underground, in a spherical form. Its interior, bizarrely, has complete life support yet is close to sterile as its interior arrangement is constantly being changed.
It is often viewed as an important location by Sourcians for reasons unknown.