A photograph of a polar bear submerged underwater was recently chosen as the grand prize winner of the 2013 National Geographic Photography Contest. Taken by photographer Paul Souders, the image also won the Nature category. Souders receives $10,000 plus a trip to Washington, D.C., where he’ll take part in the National Geographic Photography Seminar next month at Nat Geo’s headquarters.

The contest consists of three categories – Nature, Places, and People – with an overall winner chosen. National Geographic Senior Photo Editor Susan Welchman, joined by photographers Stephanie Sinclair and Ed Kashi, pored through more than 7,000 entries from 150 countries, spending hours before shortlisting the prize contenders. Photographer Cecile Baudier won the People division for a portrait of two identical twins in Denmark, while Adam Tan won the Places division for an image of old town in China being transformed.

In National Geographic’s Proof blog, Monica Corcoran did a Q&A with Souders about how he got the shot, as well as Souders’s experience as a wildlife and newspaper photographer. There is also a short video (below) of the three judges going through the selection process. You can view the rest of the runners-up here, and all the entries here.