While the same standard list may come to mind whenever you ponder the United States' National Parks, it is our hope here at HuffPost Green that this slideshow of our top ten best national parks you don't know about may just rearrange your mental checklist.
August 15th-16th marks the last in a series of three fee-free weekends to many United States National Parks. Here is the directory of national parks with waived admission.
Ready for a trip? Find a park near you or read up on the National Park Service's Family Fun activities.
To step your visit up a notch, why not participate in Geocaching, a global game in which participants hide geocache treasure, revealing its location via GPS device, and then geocachers search for the buried surprise. Get started here.
After voting on your favorite secret retreat, tell us what we've missed. What are you favorite National Parks?