At the mighty Hudson Bay the Arctic extends its icy reach deep into the North American continent. Further south than anywhere else on earth. The rhythm of the tides determines everything here. The mouth of the Churchill River is one of the most important estuaries in Western Hudson Bay. Every year, the frozen waters of Hudson Bay open up for just a few months. And this icy landscape transforms into a vast wetland, teeming with life. During this time the Churchill River estuary becomes the setting for some of the greatest natural spectacles on earth.