Archeï Oasis, Chad

Photograph by George Steinmetz, National Geographic

August 23, 2006

Knee-deep wading is bliss for camels in Chad's Archeï, a canyon whose trapped waters hold a zoological surprise. Fertilized by beasts' droppings, algae are eaten by fish that are preyed upon by an isolated group of crocodiles.

Photograph and text from the March 1999 feature story "Journey to the Heart of the Sahara."