In 2006, Joel Sartore began photographing one animal at a time; 18,000 species later, his Photo Ark has become a global conservation movement fighting to save wildlife from extinction

In 2006, Joel Sartore began photographing one animal at a time; 18,000 species later, his Photo Ark has become a global conservation movement fighting to save wildlife from extinction

Science News: In a world where species can disappear before most people even know they exist, photographer Joel Sartore has spent two decades making sure wildlife i.