Covering 29 acres, the world's largest office building is this structure in Arlington, Virginia
... Total Land 
Area: 583 acres (236 hectares); Area covered by Pentagon building: 29 acres... [DOC] [TLE] The Pentagon Building (1941-1943) - ASCE Virginia History ... [PAR] CIVIL ENGINEERING IN VIRGINIA ... "The Pentagon, headquarters of the 
Department of Defense, is the world's largest office building.