Conservation and restoration Historic buildings 108 Architecture 71 Historic sites 45 City planning 29 Congresses 28 Monuments 20 Buildings, structures, etc 18 Bibliography 17 Buildings 17 Books 15 History 15 Historic preservation 14 Antiquities 13 Urban renewal 13 Architecture, Domestic 12 Periodicals 12 Landscape protection 11 Manuscripts 11 Art objects 9 Economic aspects 8 Library materials 8 Art 7 Conservation of natural resources 7 Cultural property, Protection of 7 Repair and reconstruction 7 Cultural property 6 Environmental protection 6 Planning 6 Protection 6