Design and construction History World War, 1939-1945 7 Roads 6 Canals 5 Bridges 4 Buildings, structures, etc 4 more ... Psychiatric hospitals 4 City planning 3 Employees 3 Equipment and supplies 3 Hospital architecture 3 Political aspects 3 Prisons 3 Pyramids 3 Vertically rising aircraft 3 Weapons systems 3 Airplanes 2 Antiquities 2 Automobiles 2 Dwellings 2 Electronic digital computers 2 Fighter planes 2 Government policy 2 Historic buildings 2 History, Local 2 Holocaust, Jewish (1939-1945) 2 Housing 2 Hulls (Naval architecture) 2 Hydroelectric power plants 2 less ...