The building, now known as Building 710, was built under three feet of earth, having 36,000 square feet on two levels. Construction materials consisted of concrete and steel. Concrete was chosen for its ability to shield occupants from gamma rays, and steel added strength. The facility was built to have a fallout protection factor of 1,000 and was designed to withstand the worst nuclear attack. A power system was fed by main and back-up generators, having sensors that would automatically switch to batteries if a change in current was detected. Water was supplied by a 5,000-gallon water tank, with a back-up 800-foot deep well. A fire tank, and ground water sump pumps could provide additional water for emergencies. An air intake shaft was equipped with a shut off sensor, which would trigger a filtration system designed to remove radioactive particles. Communications facilities were contained in a “metal box�? room designed to shield sensitive equipment from electromagnetic pulse. A forty-acre field containing ten aboveground, and two belowground antennae was built adjacent to the structure. The building was designed to hold up to 300 personnel for up to 30 days with food and lodging facilities.
This building is a 2-level, square, underground facility constructed of concrete and steel. Its lower level is completely below ground, and its upper level is partially below ground, with earthen bermed walls and three feet of earth fill covering its roof. All that can be seen of the structure from the exterior include its concrete entrances, mechanical equipment, a few pipes, and antennae which rise from the Large grassed mound. The east, main entrance is a concrete 5 x 2 bay square, set into the east elevation of the mound. It has a central, double aluminum-frame door that is flanked on each side by fixed-pane, aluminum-sash window. The north and south elevations of the entrance each have two fixed-pane window bays. The roof to the entrance is flat, composed of reinforced concrete. A concrete overhanging eave above the doors and windows is supported by triangular pilasters, which separate the window bays.