The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited.
Photograph by Citron / CC-BY-SA-3.0 (courtesy Wikimedia)
For information on user permissions, please read our Terms of Service. If you have questions about licensing content on this page, please contact email@example.com for more information and to obtain a license. If you have questions about how to cite anything on our website in your project or classroom presentation, please visit our FAQ page.
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 () of the media viewer. If no button appears, you cannot download or save the media.
Text on this page is printable and can be used according to our Terms of Service.
Any interactives on this page can only be played while you are visiting our website. You cannot download interactives.