's Base Headquarters was nicknamed "The Little Pentagon" because it consisted of five long quonset huts radiating out from a central area. It was built on Henry Avenue at the east end of the Parade Ground in 1947 as administrative offices on the site of the original 217-bed Post Hospital, which dated back to September 1903. Behind the hospital was an open field used for horse grazing, troop drills, and cavalry practice. Old houses still in the area were used as doctors' quarters. On the site of the Philippine Long Distance Telephone Company office, were the nurses' quarters. During the Japanese occupation, the old hospital was used both as a dispensary and barracks. Soldiers heated water for bathing in the big steel drums directly in front of the building. Doctors and their families occupied the barns that clustered around the hospital. With the adoption of the 1979 amended Military Bases Agreement and the establishment of Philippine sovereignty over Clark AB, Base Headquarters was moved to the Clark Air Base Compound Building at the intersection of Bong and Dyess Highways. In 1986, workers began demolishing the Pentagon to make for a new Combat Support Group Headquarters Building.