• 102 Conservation of natural resources
• 53 Ecology
• 40 Renewable energy sources
• 39 Exploration
• 31 Recycling (Waste, etc.)
• 30 Wildlife conservation
• 28 Endangered species
• 27 Technological innovations
• 18 Biodiesel fuels
• 16 Climatic changes
• 15 Research
• 10 Space sciences
• 8 Aerospace engineering
• 8 Solar energy
• 7 Photographs from space
• 7 Space flights
• 6 Astronauts
• 5 Universe
• 4 Design and construction
• 4 Environmental education
• 4 History
• 3 Artificial satellites
• 3 Space shuttles
• 3 United States. National Aeronautics and Space Administration
• 2 Aeronautics

• 186 Farrow, Nick
• 100 Roberts, Paul
• 52 Holmes, Abbe
• 50 Alexander Street Press
• 35 World Wide Entertainment (Firm)
• 27 Switch International
• 26 Campbell, Craig
• 24 Dorslar, Marianne Van
• 7 Atlas, Laurie
• 1 Allan, Stuart
• 1 Malcolm-Gibbs, Wayne
• 1 Sharam, Darren

• 186 English

• 30 Outer space
• 8 Mars (Planet)
• 3 Jupiter (Planet)
• 2 Japan
• 2 Moon
• 2 Saturn (Planet)
• 2 Venus (Planet)
• 2 Yellowstone National Park
• 1 Earth (Planet)
• 1 Louisiana
• 1 Neptune (Planet)
• 1 Thailand

• 185 Documentary films
• 50 Internet videos
• 1 Nonfiction films

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