History 29 Economic conditions 23 Politics and government 13 Social aspects 11 Social conditions 10 Economic policy 9 Description and travel 8 Civilization 7 Foreign relations 7 Political aspects 7 Blacks 6 Government policy 6 Indians of South America 6 Political activity 6 Race relations 6 Slavery 6 Architecture 5 Computer industry 5 Foreign economic relations 5 Slaves 5 Exhibitions 4 Income distribution 4 Social life and customs 4 African influences 3 Architecture, Modern 3 Brazil 3 Deforestation 3 Economic aspects 3 Environmental aspects 3 Environmental policy 3