South Nahanni River, Canada
No roads take you to the South Nahanni River. You have to fly in via charter plane, but that's the easy part. The South Nahanni is considered one of North America's premier wilderness rivers. It runs 370 miles (600 kilometers) through Canada's remote Northwest Territory.
Few people paddle the whole way, however. Typically, no more than 900 people even set on the water every year, and here's why: First, the South Nahanni is best tackled only between July and August, after the spring floods but before the short days of autumn. Also, it's marked by long stretches of powerful currents and rapids that test even strong canoeists with whitewater experience. Rapids range from Class II, which may include log jams, gravel bars and jutting boulders, to Class IV, which carry the risk of forceful waves and circular, sucking currents called boiling eddies.
But the South Nahanni is also a Canadian Natural Heritage River. The calmer stretches, where the current flows at a leisurely 2 miles (3 kilometers) an hour, let you appreciate the breathtaking natural beauty that merits that designation. Pine and aspen forests give way to emerald green fields that lead to distant blue-gray mountains streaked with snow. Large tufa mounds, deposits of calcium carbonate, rise like giant molars. As for wildlife, look for moose, caribou, wolverines, trumpeter swans, Dall's sheep and grizzly bears. Don't be surprised if you spend from five days to two weeks taking it all in.