Kluane / Wrangell-St. Elias / Glacier Bay / Tatshenshini-Alsek

Nowhere outside the polar regions holds more ice than this immense wilderness spanning the Canada–United States border, where four parks in Yukon, British Columbia and Alaska protect a single sweep of glaciers, icefields and some of North America's highest mountains. Grizzly bears, caribou and Dall's sheep roam valleys that remain almost entirely roadless. First inscribed by UNESCO in 1979, the World Heritage Site was enlarged in stages into one of the biggest protected areas on Earth.