Home to over 100,000 caribou and more polar bears than we care to think about, ANWR is like the Serengeti under snow. Winter visitors don't go for the creature comforts—temperatures hover around 20 below in March—but the scenery is hard to beat. The tundra is frozen smooth, the vivid aurora borealis dances at night, and wolverine, ptarmigan, caribou, moose, fox, and, yes, polar bear spottings are common. With the rounded Brooks Range to one side and the frozen Beaufort Sea to the other, you'll mush your own sleds, trade with the local Inuit for (chewy, tasteless, calorie-packed) raw whale blubber, and build half-igloos by your tent for wind protection. And the preferred mode of transportation here—100-pound malamutes—keep the polar bears at a comfortable distance. OUTFITTER: Alaskan Arctic Expeditions; $350 per day, including meals, dogs, and extreme-weather gear; alaskanarcticexpedition.com