• 24 Videos, Slides, Films

• 21 History
• 21 Plate tectonics
• 12 Geology
• 12 Internal structure
• 6 Geomorphology
• 5 Volcanoes
• 4 Geography
• 4 Origin
• 3 Anthropology
• 3 Ecosystem management
• 3 Evolution
• 3 Human beings
• 3 Primates
• 3 Study and teaching
• 2 Volcanism
• 1 Alps
• 1 Asteroids
• 1 Catastrophes (Geology)
• 1 Collisions with Earth
• 1 Effect of environment on
• 1 Eruptions
• 1 Glacial epoch
• 1 Great Lakes (North America)

• 24 Films Media Group
• 4 Infobase
• 3 BBC Worldwide Ltd
• 3 National Geographic Television & Film

• 24 English

• 13 Earth (Planet)
• 2 Solar system
• 1 Arizona
• 1 Atacama Desert
• 1 Atacama Desert (Chile)
• 1 California
• 1 Canada
• 1 Chile
• 1 Death Valley (Calif. and Nev.)
• 1 Grand Canyon (Ariz.)
• 1 Hawaii
• 1 Iceland
• 1 Indian Ocean Region
• 1 Indonesia
• 1 Italy
• 1 Krakatoa
• 1 Krakatoa (Indonesia)
• 1 Ness, Loch
• 1 Ness, Loch (Scotland)
• 1 New York
• 1 New York (State)
• 1 North America
• 1 Rocky Mountains
• 1 Sahara
• 1 Scotland

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