Stephen Fry explores how nearly all life on Earth is impacted by its annual journey around the sun, which includes the northern winters, which bring notably harsh conditions for polar bears.

As the North starts to face the sun, the great melt begins and there's a baby boom, but for penguins and foxes in the South, conditions are about to get harsher.

Autumn signals change and brings opportunity for many, but also huge challenges. For some, like monarch butterflies, it offers a chance to begin again or take a new path.