Today, the strange story of a small group of islands that raise a big question: is it inevitable that even our most sacred natural landscapes will eventually get swallowed up by humans? And just how far are we willing to go to stop that from happening?

We are dedicating a whole hour to the Galapagos archipelago, the place that inspired Darwin’s theory of evolution and natural selection. 179 years later, the Galapagos are undergoing rapid changes that continue to pose -- and possibly answer -- critical questions about the fragility and resilience of life on Earth.

For transcripts, see individual segment pages.