Explorers 22 Discoveries in geography 18 Discovery and exploration 18 History 17 Spanish 15 Colonies 8 Indians of North America 5 more ... Knowledge and learning 5 Description and travel 4 Admirals 3 Authors, American 3 History and criticism 3 History, Naval 3 Indians, Treatment of 3 Naval history 3 Administration 2 African Americans 2 Appreciation 2 British 2 Criticism and interpretation 2 Emigration and immigration 2 Families 2 First contact with other peoples 2 French 2 Historians 2 Historiography 2 In literature 2 Intellectual life 2 Slavery 2 Statesmen 2 less ...