S.T.A.L.K.E.R.: Shadow of Chernobyl
Several years after the Chernobyl disaster, the Zone was occupied and "repurposed" by several research projects run by the Soviet government. Facilities were constructed or expanded under the abandoned military bases and civilian factories and industrial sites in the area, and a large lab was established directly beneath Reactor 4 and its Sarcophagus. These experiments were focused primarily on various aspects of the mind, including creating and enhancing ESP in humans, psychotronic weapons, and an experiment intended to create a human hive mind: the "Collective Consciousness," or "C-Consciousness," project.