Supported by the National Geographic Society, the world’s eminent blue whale scientists embark on a revolutionary mission: They’ll find, identify, and tag California blue whales, use the DNA samples to confirm the sex of individual whales, then rejoin the massive creatures’ stunning migration when they collect at a chimera known as the Costa Rica Dome.

In this special documentary that inspired a two-season television series, scientists and other experts speculate about what the Earth, animal life, and plant life might be like if, suddenly, humanity no longer existed, as well as the effect humanity’s disappearance might have on the artificial aspects of civilization.