Great Smoky Mountains
Credit: Jerry & Barb Jividen / Getty Images

With 9 million visitors each year, the Great Smoky Mountains is the country's busiest park. That means the best way to explore it is to go off the beaten path, and traverse this park by foot. The park covers more than 800 square miles over North Carolina and Tennessee and has hiking trails throughout, dotted with old barns and churches built in the 1700s that are preserved as historical landmarks. "This park gets twice as many visitors as the Grand Canyon," said Kupper. "But that's because it's part of our national lore. Just because it's busy doesn't mean its all touristy. There's a lot the masses miss." 

Don't Miss: The Fontana Reservoir is a 480-foot dam on the southwestern edge of the park, the tallest concrete dam east of the Rocky Mountains. It's a hub for fishing, boating, swimming and provides hot showers at the trail shelter for hikers traveling the Appalachian Trail.