Destination Wild: Life in the Wilderness of The Boreal Forest | Free Documentary Nature

The boreal belt holds almost a third of the world's forest, and this film stays at ground level with the bears, wolves and tigers that depend on its cold cover. It tracks how a warming climate is already redrawing the biome around them, shown through the animals rather than narrated statistics.

Why it's free: Free on Free Documentary - Nature's own channel; the licensed distributor published it.