Blunthead Tree Snake

600 miles from the Ecuadorian coast, the Galapagos archipelago rises from the Pacific. It's an evolutionary laboratory, shaped by primordial forces, providing us with clues to the origins of life. The birth of the islands began five million years ago, as a geological hotspot travelled across the ocean floor, bubbling up lava through cracks in the crust as it went. The oldest of the volcanos are now being swallowed up by the sea, where only the crescent shaped rim of the ancient crater remains...