Jungles comprise the most diverse habitats on Earth in which only the most resilient species triumph; the fiercest jungle species include jaguars, caimans, gibbons, orangutans, spectral tarsiers, hummingbirds, and parasites.

The frozen poles are home to the planet's ultimate survivalists, including polar bears, penguins and Arctic wolves; their world is changing fast -- breaking apart under their feet -- and their resilience will be tested beyond the extreme.