Sierra Club founder John Muir spent the final year of his life in a losing battle to save the Hetch Hetchy Valley from being dammed, and although he failed in that fight, his efforts would ultimately lead to the launch of the National Park Service in 1916, which remains dedicated to protecting the country’s natural wonders so that all of America’s citizens can enjoy them.
And, if you’re willing to put in a little research, you can enjoy them for free. Not only does the National Park System offer four days a year when you can enter any of the nation’s more than 400 parks for free, but there’s also a range of options for entering hundreds of national parks for free outside the designated fee-free days.
GoBankingRates.com has put together a list of national parks, monuments, historic sites and public lands that you can visit without charge, including the most visited national park in the country – any guesses what that is? Take a look through the photos above to find out.
And if you're looking for more free travel ideas, scroll through the gallery below: