Media Credits
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Video provided by U.S. Department of Energy
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Media
Some media assets (videos, photos, audio recordings and PDFs) can be downloaded and used outside the National Geographic website according to the Terms of Service. If a media asset is downloadable, a download button appears in the lower right hand corner (
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Text
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Interactives
Any interactives on this page can only be played while you are visiting our website. You cannot download interactives.