The National Park Service is celebrating its 100th anniversary this year.
Congress created the National Park Service back in 1916. National parks existed before then, but there was no single agency to manage the entire system. According to Wikipedia, the US Forest Service actually opposed the new agency, for fear of losing control of various lands being used by the timber industry. Doesn't sound all that different from environmental-versus-industry battles from more recent history.
I've visited the oldest National Park, Yellowstone, on a couple of different occasions. I have some good memories of the neighboring Grand Teton National Park as well. Seeing the Grand Canyon is something that I think everyone fortunate enough to visit won't ever forget. I haven't been to anything close to the entire system of parks, but I certainly appreciate all the ones that I have seen.
Happy anniversary to the National Park Service. May all the places under its management stay natural and beautiful for future generations to enjoy.