Subject
Explorers
Discovery and exploration
201
History
80
Spanish
53
Description and travel
45
Travel
44
British
38
Voyages around the world
16
Indians of North America
15
Natural history
11
Naturalists
11
Discoveries in geography
10
Frontier and pioneer life
9
Admirals
8
Adventure and adventurers
6
French
6
Friends and associates
6
Pioneers
6
Travelers
6
Antiquities
5
Cartographers
5
English
5
Fur trade
5
Fur traders
5
History, Naval
5
Indians, Treatment of
5
Missionaries
5
Scholars
5
Voyages and travels
5
American
4
Archaeologists
4
Ethnology
4
First contact with other peoples
4
Photographers
4
Poets, American
4
Surveyors
4
Territorial expansion
4
Women explorers
4
Canadian
3
Conservationists
3
Court and courtiers
3
European
3
Generals
3
History and criticism
3
Mass media
3
Scientific expeditions
3
Underwater exploration
3
World War, 1914-1918
3
Artists
2
Biography
2
more ...