Photo: A frog dangles from the mouth of a crocodile in South Africa.

Stratus clouds over Inglefield Bay

The emperor penguins fight for survival and to protect their only baby in the frozen Antarctic ice desert. (via Nature - Week 6 Wallpaper - National Geographic Photo Contest 2011 - National Geographic)

(via Nature - Week 6 Wallpaper - National Geographic Photo Contest 2011 - National Geographic)

(via Whitetip Shark Picture – Bahamas Photo – National Geographic Photo of the Day)

A red-eyed tree frog clings to a branch in Costa Rica.

via http://photography.nationalgeographic.com/photography/photos/most-popular-photo-gallery/#/red-eyed-tree-frog_26498_600x450.jpg

Morning sun touches the hills and sand dunes of Inishowen, Ireland (via Ireland Picture – Travel Wallpaper – National Geographic Photo of the Day)

A layer of low clouds covers the alpine valleys of northern Italy, just south of Lake Como. The clouds are just dense enough to hide uniformly the valley and also filter the artificial lights below like they were an opaque blanket. Above the layer, moonlight and high cirrus clouds make the night less dark. You can easily recognize the round shape of Lago di Olginate and the lights of the villages all around its banks.

(via Lago di Olginate Photo – Italy Picture – National Geographic Photo of the Day)

Photo: Yosemite free climber

Photo: The Milky Way in the sky above Arches National Park