Photos of the Day Best of 2011

Photo of the Day: Best of 2011

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Cottonmouth, North Carolina

While working as a field researcher for a biodiversity study on pine plantations in North Carolina, I found this Agkistrodon piscivorus in a drainage ditch. It's seen here displaying the classic defensive posture that gives it the common name "cottonmouth."

Lightning, Arizona

This is a time exposure of four lightning strikes over Scottsdale, Arizona.

Arches National Park

,The mighty weight of the entire Milky Way teeters precariously on Balanced Rock in Arches National Park

Freestone Climb, Yosemite Falls

.Kate Rutherford can't hear a thing while climbing so close to the roar of Yosemite Falls. She can't find much to hang on to either. The water polishes the rock "like glass." Wearing tape on her hands, she has to repeatedly jam them into fissures for the ascent. Spectacular scenery makes up for the discomfort. The climbing route is called Freestone, Rutherford says, because "it's a peach of a route.",

Polar Bear and Cub, Svalbard

As we watched from our Zodiac, this polar bear gave her cub a lift as she swam across the fjord, shaking herself dry after emerging from the water with her cub hanging on. Polar bear cubs have been known to occasionally ride on the backs of their mothers as they swim together in Arctic waters, possibly to reduce exposure to cold.

Matterhorn

Radiant at sunrise, the Matterhorn towers over Riffel Lake near Zermatt,Switzerland

Badab Sourt Spring, Iran

.Main Spring in Badab Sourt in wintertime. Badab Sourt Spring is in the city of Sari in Iran, in the Alborz mountains, altitude 1,840 meters.

Lago di Olginate, Italy

,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.,,