National Geographic's 2017 Nature Photographer of the Year contest is underway. Photographers around the world are invited to submit their work at natgeo.com/photocontest in any or all of four categories: Wildlife, Landscape, Underwater and Aerial.

The grand prize winner will receive $10,000 (about £7,500), publication in National Geographic Magazine and a feature on National Geographic's Instagram account, @natgeo. Entries close on Friday 17 November 2017, and the winners will be announced in December 2017. For details and official contest rules, please visit natgeo.com/photocontest. IBTimes UK showcases some of the most spectacular entries submitted over the past two weeks.