Canada's Yukon Territory announced on Tuesday that it has opened one of the largest unbroken wilderness areas in North America to mining and mineral exploration.

The government's decree stunned indigenous leaders, who support a 2011 plan developed under Yukon land claims treaties that would have maintained the wilderness character of 80 percent of the area, which is known as the Peel watershed region. The government's new plan all but reverses that figure, opening some 71 percent of the watershed to mining.

The Yukon features some of Canada's highest peaks and largest glaciers, as well as tremendous expanses of lake-dotted tundra, boreal forests, and wetlands. (See "Yukon: Canada's Wild West" in the February issue of National Geographic magazine.) It's also rich