Lonesome George, a Pinta Island subspecies of Galápagos giant tortoise believed to be the last of his kind, died on Sunday, June 24.

(Airs Sunday, March 7) Around the globe, unique and fascinating species face extinction. Follow the plight of these creatures and the dedicated conservationists who fight for them.

NATURE's "The Reptiles: Turtles and Tortoises" takes a close look at ancient creatures marching slowly through the millennia.