This striking image from the Week 11 Gallery of National Geographic's 2012 Photo Contest depicts a drowned sheep most of the way submerged in a frozen swamp—but what's not submerged has been eaten away by birds, exposing a skeleton still encased in the otherwise untouched body of a sheep.

John Berger pointed out that what makes photography so strange and unforeseeable in its potential consequences is that its primary raw materials are really light and time.

"Photographs bear witness to a human choice being exercised in a given situation," Berger wrote. "A photograph is a result of the photographer's decision that it is worth recording that this particular event or this particular object has been seen. If everything that existed were continually being photographed, every photograph would become meaningless."

But in this case, the twist is that there seems to be very little decision-making of any kind going on—how could a human not take this picture? Nature in the form of the hungry bird mouth and the hungry human eye have ganged up on the sheep. They are in cahoots. The sheep is just stuck there, a spectacle waiting for a photograph.