1. Great Smoky Mountains National Park - There are more than 800 miles of hiking trails across north carolina and tennessee.

2. Yosemite National Park - John Muir led the crusade for the creation of the california park in 1890.

3. Rocky Mountain National Park - THe park contains 150 lakes and 450 miles of streams. Plus ecosystems ranging from Wetlands to Alpine Tundra.

4. Zion National Park - The park's striking vertical topography - rock towers, sandstone canyons and sharp cliffs - attracted 4.2 million visitors in 2016.

5. Yellowstone National Park - The world's very first national park remains the showpiece of the national park service.