While National Parks blanket 84.6 million acres, or 3.4 percent, of the United States, if you live in a bustling city, it’s easy to forget they’re even there. But America’s 58 National Parks—which span 27 states—are full of natural wonders just waiting to be discovered. Whether you’re a nature-lover, adventurer, or a city-dweller dreaming of seeing a bit of green, here are 15 reasons to visit the National Parks this summer.

1. NATIONAL PARKS ARE AFFORDABLE …

The perfect vacation destination for travelers on a budget, National Park entrance fees vary, but even the most iconic destinations will only set you back a few bucks. A vehicle permit for the Grand Canyon, for instance, only costs $30, while weeklong individual passes to Yellowstone cost a measly $15 per person. Not only that, but the National Parks periodically offer free entrance days, opening the parks up to everyone for no cost. This summer, all National Park Service sites that normally charge a fee will be free from August 25 through 28, in honor of the 100th birthday of the National Park Service.

2. … AND CONVENIENT.

With 58 parks in 27 states, there’s a good chance you won’t have to travel far to find a National Park to explore. California has the most parks with nine, followed by Alaska with eight and Utah with five. National Parks can be found throughout America, from Biscayne in the Florida Keys, to Acadia on the ocean shore of Maine; from Oregon’s Crater Lake and Washington’s Mount Rainier on the West Coast to South Dakota’s Badlands and North Dakota’s Theodore Roosevelt in the Central U.S. 

3. YOU’LL DISCOVER NATURAL WONDERS.

The wonders on display in America’s parks go far beyond a few bushes and trees. There are volcanoes (Lassen Volcanic, California) and glaciers (Kenai Fjords, Alaska), mysterious caves (Mammoth Cave, Kentucky) and snow-topped mountains (Mount Rainier, Washington). Visit the Petrified Forest in Arizona to see fossilized trees or Mesa Verde in Colorado to explore the ancient cliff dwellings of the Ancestral Puebloan people. No matter which park you choose, the National Parks protect some of America’s greatest natural treasures. 

4. THEY ENCOMPASS A WIDE VARIETY OF ECOSYSTEMS.

Much like America itself, the National Parks encompass a vast range of ecosystems. Whether you’re craving ice and snow or a tropical vacation, there’s a National Park that will fit your interests—and, as noted already, there’s a good chance it’s a whole lot cheaper than other vacation destinations you might be considering. 

5. THEY’RE EDUCATIONAL.

A trip to a National Park is a great opportunity to teach your child (or learn more on your own) about nature, science, conservation, and history—all while having fun. Most parks offer tours with professional guides who will teach you and your family all about the park. Some even offer classes on everything from geology and natural history to photography and fly-fishing.

6. THEY’RE PERFECT FOR ADRENALINE JUNKIES …

The National Parks have plenty of adrenaline-pumping activities for even the most fearless adventurers. Rock climbers can scale the vertigo-inducing Half Dome in Yosemite or climb the craggy heights of Devils Tower National Monument in Wyoming. At the Great Sand Dunes in Colorado, those with a need for speed can zip down the park’s eponymous dunes on specially-made sandboards and sleds. Bicyclists, meanwhile, can explore many of America’s National Parks on paved roads or dirt paths, with plenty of trails for road and mountain bikers alike.

7. … AND UNDERWATER ADVENTURERS.

The National Parks offer a wide range of scuba diving, snorkeling, and other watersport opportunities. At Dry Tortugas National Park in Florida, for instance, divers can swim with the fish and explore 67,000 acres of coral reefs, soft sand, and even shipwrecks. But you don’t have to travel to a subtropical climate to find great diving: Parks all over the country, from Acadia National Park in Maine to Grand Teton National Park in Wyoming, offer all kinds of underwater diving adventures.

8. THEY’RE GOOD FOR YOUR HEALTH.

Studies have shown that spending time outdoors has a vast range of health benefits, from boosting your immune system to enhancing creativity. In fact, according to one study, just seeing trees can make us feel healthier. Which means vacationing in a National Park is a great way to ensure you return home feeling better than when you left.

9. THEY’RE A GREAT WAY TO EXPLORE A NEW REGION …

Planning a vacation to an out-of-state National Park is a great way to discover a new region or explore the United States. Take a road trip to Yellowstone and discover America along the way or visit a National Park near an urban area to get the best of both city and country. Visiting a National Park is a great way to anchor a summer vacation and let you discover new parts of the country.

10. … OR LEARN MORE ABOUT YOUR HOME STATE.

Visiting a National Park in your home state can also be a wonderful learning experience, especially if you’re a city-dweller. Exploring a National Park close to home will teach you and your family all about local flora and fauna, and give you a sense of what your city might have been like before it was settled by humans. 

11. THEY’RE IDEAL FOR RELAXATION.

America’s National Parks aren’t just for adrenaline junkies. They’re also a romantic place to watch the sun set with a loved one, and the perfect place to meditate or unwind in solitude. You can even visit Hot Springs National Park in Arkansas and take a soothing bath in the park’s thermal waters for a natural spa vacation.

12. YOU CAN ESCAPE TECHNOLOGY …

The National Parks offer a rare opportunity to go tech-free. A National Park camping trip offers a unique opportunity to spend time with friends and family without the interruptions of constantly buzzing smartphones. 

13. … AND LET YOUR FEET WANDER.

With thousands of miles of hiking trails, there’s no better place to go for a walk than in one of America’s National Parks. Whether you're a beginning hiker going on a day trip or an experienced backpacker looking for a camping adventure, the National Parks are full of trails for all skill levels.

14. EACH PARK HAS A UNIQUE HISTORY.

All of America’s National Parks have a unique story to tell. Some like Oregon’s Crater Lake and South Dakota’s Wind Cave were founded by President Theodore Roosevelt and are intrinsically linked to America’s political history, while others tell even older stories, about ancient peoples and the early history of the Earth itself. Badlands National Park, for instance, is full of ancient fossils, while Mesa Verde National Park is home to the cave dwellings of the ancient Pueblo people.

15. THERE’S SOMETHING FOR EVERYONE.

The National Parks are often called America’s backyard, and for good reason: They have something for everyone. They can give children their first experience with the great outdoors and let adults reconnect with nature. They can teach us lessons about history and conservation, or simply provide a much-needed escape from the daily grind. No matter who you are, there are innumerable reasons to give the National Parks a visit this summer.