The editors of Smithsonian magazine have just announced the 50 finalists in their 10th annual photo contest. They've kindly allowed me to share several of these images here, including some great shots from each of the competition's five categories: The American Experience, The Natural World, People, Travel, and Altered Images. Be sure to visit the contest page at Smithsonian.com to see all the finalists, and vote in the Reader's Choice Awards as well.