National Geographic is renowned for its professional photojournalism, but the photos that readers themselves shoot and submit are often just as amazing. Every weekday, the magazine's editors choose their Daily Dozen favorites, and those that are rated highest by online visitors are made available for download in National Geographic's Weekly Wrapper as computer wallpaper. The photograph below was taken at a waterfall in West Virginia; a long exposure time reveals a whirlpool swirling at the waterfall's base.