The finalists of Smithsonian.com's 12th Annual Photo Contest have been announced. Readers are invited to vote for a special Readers' Choice Award. Polling will remain open until 30 March, and winners will be announced on 31 March.

Smithsonian received over 26,600 submissions spanning six categories: The Natural World, Travel, People, Americana, Altered Images and Mobile. Ten finalists from each category have been selected. IBTimes UK publishes a selection of the finalists; you can see more here.