National Geographic has once again opened its annual photo contest, with the deadline for submissions coming up on Saturday, November 30. One first-place winner will be chosen from each of the three categories, and the winning photographs will be published in National Geographic magazine. The overall grand-prize winner will be announced in December of 2013. National Geographic was kind enough to let me choose among its entries so far for display here on In Focus. Gathered below are 39 images, with captions written by the individual photographers.