© James Smart / National Geographic Photo Contest

© Marco Grassi / National Geographic Photo Contest

© Stas Bartnikas / National Geographic Photo Contest

© Surawut Sudha / National Geographic Photo Contest

© Martin L. / National Geographic Photo Contest

© Achmad Sumawijaya / National Geographic Photo Contest

© Ludwig Wagner / National Geographic Photo Contest

© Eric Lew / National Geographic Photo Contest

© Marco Grassi / National Geographic Photo Contest

© Sho Shibata / National Geographic Photo Contest