The sun returns after months of darkness, dynamically transforming the landscape. Millions of migrants join the hardy residents as they find mates and begin to breed.

Summer creates a window of opportunity that attracts hordes of visitors who cram a lifetime of drama into a few short months as they feed, fight, and rear their young.

Polar landscapes are transformed as the big freeze returns. Most animals leave on epic journeys, some now battle to breed, and, for the hardy few, it’s a time of opportunity.

During winter most animals abandon the polar regions, but a few extreme survivors remain. This is the story of their strategies and battles to survive the planet’s harshest weather.

Humans have no natural protection against the cold of the polar regions. Why, therefore, have we been visiting these remote places for thousands of years; and what keeps us going back today?

A look at how scientists measure changes in the polar regions and what those changes mean for the animals and people who live there, as well as the rest of the planet.