Imagine being the very last surviving member of your kind on Earth, carrying millions of years of evolutionary history alone. For decades that burden was carried by a 165-pound giant tortoise known as Lonesome George, the rarest creature in the world.

This episode explores George's century-long life, his discovery on a devastated island, the desperate global scramble to save his lineage, and how even after death he remains a profound symbol of conservation. It also reveals the wild postmortem genetic mysteries that may one day strip him of his title as an endling.

• His 1971 discovery on Pinta Island, ravaged by feral goats that stripped vegetation to bare rock
• The 40-year bond with caretaker Fausto Llerena and the unclaimed $10,000 reward for a suitable mate
• Decades of failed mating attempts and inviable eggs with  ...