An arctic expanse

The mighty Brooks Range marks a 700-mile-long continental drainage divide in North America's far northern reaches. Here, rivers running north empty into the Arctic Ocean, while those running south flow into the Yukon River. This remote massif is estimated to be 126 million years old and contains a rich fossil record of the ancient seabed it once was. Found among the tundra and stands of spruce trees are fossilized corals from the Cambrian period. The mountains also teem with living wildlife, with a portion of the range lying within the Arctic National Wildlife Refuge.