National Park systems are one of the best ways to truly see nature as it was meant to be.
Typically a National Park is a large piece of land that is set aside by a national government in order to better preserve the wildlife and natural beauty of an area.
In these areas most governments restrict development, hunting, mining, or other activities.
The idea is that by protecting these areas, wildlife and nature will be sustained. People can therefore visit National parks and get away from the urbanisation and pollution that make up the cities, to go enjoy the peace and beauty of the countryside.
Yellowstone National Park was the very first national park in the world, and set a standard by which many other countries began to follow, setting aside land for the sole purpose of maintaining nature and wildlife and nothing else.
Through the use of the national park system many states have even been able to create a huge tourism benefit for their local economies. This of course is very true with the Grand Canyon, Denali National Park, Yellowstone, and many others which take advantage of massive amounts of tourists that visit the area each and every year. Without these established parks the number of tourists would be substantially less as the facilities and infrastructure wouldn't be in place to allow for observation of these historic parks.