• 40 Videos, Slides, Films

• 21 Historical geology
• 21 Plate tectonics
• 12 Internal structure
• 9 Geology
• 7 Geography
• 6 Geomorphology
• 6 Study and teaching
• 5 Volcanoes
• 3 Civilization, Ancient
• 3 Human ecology
• 3 Methodology
• 3 Nationalism
• 3 Research
• 3 Slopes (Physical geography)
• 3 Sociology
• 2 Economic aspects
• 2 Effect of human beings on
• 2 Human geography
• 2 Nature
• 2 Political anthropology
• 2 Social conditions
• 2 Social life and customs
• 2 Social structure

• 40 Films Media Group
• 40 Films for the Humanities & Sciences (Firm)
• 10 Infobase
• 6 Public Broadcasting Service (U.S.)
• 3 BBC Worldwide Ltd
• 3 Zweites Deutsches Fernsehen
• 2 555 Productions, Inc
• 2 American Public Television
• 1 Agency for Instructional Technology
• 1 Java (Firm)
• 1 Telepool GmbH

• 40 English
• 1 Spanish

• 13 Earth (Planet)
• 7 Asia
• 6 India
• 6 South Asia
• 4 Europe
• 2 Africa
• 2 Africa, Sub-Saharan
• 2 Japan
• 2 Solar system
• 2 United States
• 1 Arizona
• 1 Atacama Desert
• 1 Atacama Desert (Chile)
• 1 California
• 1 Canada
• 1 Chile
• 1 Costa Rica
• 1 Death Valley (Calif. and Nev.)
• 1 Grand Canyon (Ariz.)
• 1 Hawaii
• 1 Iceland
• 1 Indian Ocean Region
• 1 Indonesia
• 1 Italy
• 1 Krakatoa

Limit year range