GDC-7 SAC HEADQUARTERS Completed in December, 1956, at a cost of eight million dollars. Has three stories above ground and three stories below. It is the control center of SAC's far-flung defense system. OMAHA, NEBRASKA GENERAL DISTRIBUTING COMPANY. MIRRO-KROME ® CARD BY H. S. CROCKER CO., INC., SAN FRANCISCO 1, CALIF.