Ellesmere is a vast desert island—the 10th largest island in the world, not a tropical paradise but an icy wilderness at the top of the world, a place of undulating ice fields, rugged gray-black mountains, and boulder-strewn glaciers. For nearly five months a year the sun is not seen here at all, but in midsummer it shines for 24 hours a day, not even dipping below the northern horizon. The island’s northern extremity is Cape Columbia, just a stone’s throw—497 miles (800 kilometers)—from the North Pole. Its highest point is the peak of Mount Barbeau, 8,583 feet (2,616 meters) above sea level. Deep fjords, such as Archer Fjord, indent its coastline. The cliffs here plunge 2,300 feet (700 meters) to the tumultuous sea below. Winter temperatures can drop to -49°F (-9°C), and the sea freezes solid. The land, however, remains dry for most of the year. Surprisingly there is little precipitation; no more than 2.5 inches (60 millimeters) a year. Summer temperatures—from late June to late August— rarely rise above 45°F (7°C), although it can be warmer on days without clouds. It is a true wilderness, with just three settlements— Eureka, Alert, and Grise Fjord.