Sliding Rock (Pisgah National Forest, NC)
Credit: Kennan Harvey / Getty Images

Some of the country's best natural waterslides are hidden in the thickets of the Blue Ridge Mountains, where millennia of rainstorms have carved smooth slides over great sheets of rock. The most popular is Sliding Rock, but if it's packed, head 40 miles south to the area's best-kept secret: Nantahala National Forest's Turtleback Falls, where a cold rush of water pushes riders over a slick granite dome and off a 20-foot ledge into a swimming hole. Warning: A few hundred yards downriver is the 200-foot Rainbow Falls, which you shouldn't go over without a death wish.