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.

Smithsonian photo contest 2015
Finalist, Natural World: A snake swallows an unlucky frog near the Arenal Volcano, Costa RicaNicolas Reusens, Madrid, Spain
Smithsonian photo contest 2015
Finalist, Natural World:Light refracts through the curves of a breaking wave, New South Wales, AustraliaRay Collins, Sydney, Australia
Smithsonian photo contest 2015
Finalist: People: An albino child attends an exhibition about albinos at the Ethnology Museum of ValenciaAna Yturralde, Valencia, Spain
Smithsonian photo contest 2015
Finalist: People: Onno, a teenage girl from the Arbore tribe in the Ommo Valley, EthiopiaMatjaz Krivic, Ljubljana, Slovenia
Smithsonian photo contest 2015
Finalist: Americana: Two presidents: US President Barack Obama stands in the Oval Office of the White House in Washington, DCOlivier Douliery, US
Smithsonian photo contest 2015
Finalist: People: Women sew a fishing net in Vinh Hy bay, Ninh Thuan, VietnamPham Ty, Vietnam
Smithsonian photo contest 2015
Finalist: Travel: Girl looking out the window of a slow train, while an old woman sleeps, Kayah State, MyanmarJorge Fernandez, Spain
Smithsonian photo contest 2015
Finalist, Natural World: A harmless but very restless snake in Selva Verde Lodge, Sarapiqui, Costa RicaAlvaro Cubero Vega, Costa Rica
Smithsonian photo contest 2015
Finalist, Natural World: Grizzly bear walking in an estuary in Lake Clark National Park, AlaskaKevin Morgans, Wirral Peninsula, Cheshire, UK
Smithsonian photo contest 2015
Finalist: Travel: Young Buddhist novices playing at Hsinbyume Pagoda, MyanmarSergio Carbajo Rodriguez, La Garriga, Spain
Smithsonian photo contest 2015
Finalist: Travel: Children play in Bani, Burkina FasoMatjaz Krivic, Ljubljana, Slovenia
Smithsonian photo contest 2015
Finalist: Travel: Densely packed Christian cemetery in Hong KongBrian Yen, Hong Kong
Smithsonian photo contest 2015
Finalist, Americana: July 4th celebration on the bank of the Willamette River in Independence, OregonAnne Marcom, McMinnville, Oregon