Glaciers, wild horses, sand dunes, and supervolcanoes: North America's national parks offer a thousand different adventures. On August 25, they'll celebrate their hundredth birthday. In honor of all our wild spaces, here are just a few of the incredible sights that are only a trip away.

1. Yellowstone National Park

One of the world's best-loved national parks, Yellowstone contains half of the world's geothermal features. From bubbling mud pots to rainbow pools and sky-high geysers, there's only one place like this on earth.

2. Blanchard Springs Cavern, Ozark National Forest

This cave system is a gem of the Ozark-St Francis National Forest; guided tours travel through warmly-lit limestone rooms and sparkling underground formations.

3. Bryce Canyon National Park

Bryce Canyon is home to the world's largest collection of "hoodoos"--stunning rock spires created by erosion. It's particularly striking in winter, when snow stands out against the bright red sandstone.

4. Everglades National Park

The Everglades may be a swamp, but there's a lot more to see than you might think. Canoe through mangrove and cypress forests, or check out the classic, wildlife-rich grass marshes.

5. Redwood National Park

Home to the tallest trees on earth, Redwood is a classic, beautiful place to unwind. From rugged coastline to prairies and the namesake massive sequoia forests, Redwood offers visitors a variety of special landscapes to enjoy.

6. Kenai Fjords, Alaska

Visit Kenai Fjords for a quick trip to the ice age: centuries-old glaciers linger here, slowly returning to the sea. Keep an eye out for marine life--this is a great spot to find whales or orcas!

7. Olympic National Park

From rugged mountains to old-growth forests and lush alpine grassland, Olympic never fails to wow visitors with its diverse landscapes. Time your visit with the stunning bloom of wildflowers, from lowlands all the way up to high-altitude meadows.

8. Great Sand Dunes National Park

Sand-sled or hike up Star Dune--America's tallest dune, at 750 feet. Also listen for an eerie sound when the wind picks up: sand rubs against itself and "sings."

9. Assateague Island National Seashore

A small, windswept island off the coast of Maryland, Assateague is home to some of America's last wild horses.

10. Rocky Mountain National Park

Few places preserve the harsh beauty of American wilderness like the Rockies; dramatic vistas and abundant wildlife make this one of America's most iconic wild spaces.

11. Acadia National Park

Acadia is loved for its granite hills and spectacular Maine coastline. Visit in the fall for a breathtaking, color-rich view.