National Geographic's 2017 Nature Photographer of the Year contest is underway. Photographers around the world are invited to submit their work at 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 IBTimes UK showcases some of the most spectacular entries submitted over the past two weeks.