Twice a day, air handling units pump fresh air through a labyrinth of air ducts to maintain a 21-23°C temperature at 60-80% humidity. Two transformers are on alternating duty to supply electricity. The water reservoir is filled with potable water from the adjoining Bijela Neretva river. Still modestly filled fuel tanks are ready to supply stand-by emergency generators. Various archaic-appearing mechanical systems would have guaranteed automatic seclusion from the outside world and the engagement of self-sustainable building systems, providing an autarkic survival space for 350 people over a period of months.