Submit your entry online to the 2012 Traveler Photo Contest in any of these four categories: Travel Portraits, Outdoor Scenes, Sense of Place, and Spontaneous Moments. Prizes include a Galapagos Photography Expedition, photo workshops, and more.

See a photo of an expedition tent on the rim of the Nyiragongo volcano by Carsten Peter and download free wallpaper from National Geographic.

A holiday comet, Icelandic auroras, and the Milky Way feature among the winning shots from the International Earth and Sky Photo Contest.

Perched on precarious cliff ledges, centuries-old log coffins and "body jars" are the only known traces of an unknown Cambodian tribe

See a photo of a climber weaving through razor-sharp pinnacles in Madagascar by Stephen Alvarez, from National Geographic.

See a photo of a kayaker on the still waters of a fjord in Greenland, from National Geographic

For many of Earth’s creatures, time is running out. Half of the world’s plant and animal species will soon be threatened with extinction. The goal of t

Even 20 years photographing animals couldn't have prepared Joel Sartore for some of the creatures he has encountered working on a series that aims to showcase biodiversity in the United States.

Even 20 years photographing animals couldn't have prepared Joel Sartore for some of the creatures he has encountered working on a series that aims to showcase biodiversity in the United States.

See a photo of cavers at the entrance to Ora Cave on New Britain Island in Papua New Guinea by Stephen Alvarez, from National Geographic.