WHEN NATIONAL WILDLIFE INAUGURATED ITS ANNUAL PHOTO CONTEST 43 YEARS AGO, contestants submitted just a few hundred images, all of them documenting the harmful impact of pollution on wildlife. That year’s Grand Prize winner portrayed a dead, oil-soaked cormorant. This year the editors received more than 32,000 entries in seven categories ranging from Backyard Habitats to Baby Animals. Yet despite their greater diversity, many entries still mirror NWF’s conservation priorities. This year’s Grand Prize winner, for instance, features a polar bear, a species severely threatened by climate change. On the day this bear was photographed, the temperature on northern Canada’s Hudson Bay soared above 90 degrees F during a record-breaking heat wave.

View a slideshow of the winning images here and the stories behind each image are available here.