Bent Northrop Memorial Library

Their magic tree house takes Jack and Annie to the Arctic, where a polar bear leads them onto very thin ice.

A mother polar bear answers the questions of her two curious cubs about what lies beyond their cozy winter den as they wait for spring to arrive.

"From the top of the world, Hudson Bay looks like an enormous paw print on the torso of the continent, and through a vast network of lakes and rivers, the water in this bay connects to oceans across the globe. Here, at the heart of everything, walks Nanurjuk, or Nanu, one polar bear among the six thousand that traverse the 1.23 million square kilometres of ice and snow covering the bay. For millennia, Nanu's ancestors have roamed this great expanse,...