* On a trip to the Dakotas in 1832, artist George Catlin had what is thought to be the first inspiration for, as he put it, "a nation's park, containing man and beast, in all the wild and freshness of their nature's beauty."
* In 1872, President Ulysses Grant signed the law that made Yellowstone a national park - the first in the United States and the world.
* Railroad companies were early backers of park creation. They built grand hotels to lure tourists - who traveled by rail - to the parks.
* The National Park System covers 83.3 million acres, with sites in every state except Delaware. Its 376 areas include 54 national parks, 73 national monuments, 4 national parkways, 10 national seashores, and more.
5 Most-Visited National Parks (1997)
1. Great Smoky Mountains (N.C., Tenn.) 9.9 million
2. Grand Canyon (Ariz.) 4.8 million
3. Olympic (Wash.) 3.8 million
4. Yosemite (Calif.) 3.7 million
5. Yellowstone (Mont., Idaho, Wyo.) 2.9 million
5 Least-Visited National Parks (1997)
1. Kobuk Valley (Alaska) 2,781
2. Gates of the Arctic (Alaska) 6,949
3. Lake Clark (Alaska) 9,173
4. Isle Royale (Mich.) 21,381
5. North Cascades (Wash.) 27,203
Largest national park: Wrangell-St. Elias National Park and Reserve in Alaska - 8.3 million acres.
Smallest national park: Hot Springs in Arkansas - 5,549 acres.
Most-expensive parks: Grand Canyon, Grand Teton, Yellowstone, Yosemite. (Admission fee of $20 per car, $10 for hikers.)
Bargain parks: Capitol Reef (Utah) - cars $4, hikers $2. Kenai Fjords (Alaska) - cars $5, hikers $3. Saguaro (Ariz.) - cars $4, hikers $2.