One of the most geothermally active spots in the US, Yellowstone National Park offers its visitors the chance to hang out with geysers, scout out bears and wolves, stand next to waterfalls, and smell the earth’s sulfur. There’s nowhere quite like it—which is why this park receives roughly a few million visitors each year. To skip the driving woes, hop on a tour, where a guide can take you to the best spots. Or, opt for a kayaking trip or backcountry geyser tour to leave the crowds behind.

Once home to hundreds of glaciers, Montana’s Glacier National Park now claims roughly two dozen as the world warms. Go to admire carved peaks, glistening lakes, and alpine meadows. Between late May and September, you’ll need a reservation to drive through the park via the spectacular Going-to-the-Sun Road (in addition to your national park pass). If you go in winter, you won’t need a reservation, which means it’s an excellent time to visit.

One of the most spectacular glacier-carved valleys in the world, Yosemite National Park was a favorite of John Muir, Ansel Adams, and Teddy Roosevelt. Driving down Yosemite Valley feels like the stuff of Avatar, with 2,425-foot (739-meter) Yosemite Falls and El Capitan monoliths lurking high among their granite brethren. Most visitors spend their time in the narrow Yosemite Valley, which is only 7.5 miles (12.1 kilometers) long, but the rest of the park is considerably less crowded.

It’s not every day that you get to gaze into the lava lake of an active volcano. But you can (usually) at Hawaii Volcanoes National Park, which is on the big island of Hawaii. (When the lava is flowing, sometimes the sky even glows orange.) The park makes for a phenomenal experience even when the rocks aren’t liquid, as you can still enjoy black-sand beaches, fresh lava rocks, views across the Pacific, and more.

Denali National Park in Alaska is 6.1 million acres (2.5 million hectares). You won’t find a single “official” trail; there’s only wilderness to inspire your imagination. Despite its large size, there’s only one road that goes through Denali. The formerly 92-mile (148-kilometer) road through the park is now closed at its halfway point thanks to a landslide. While bus tours will take you as far as possible, to get that deep, backcountry experience, you’ll want to opt for a flightseeing tour.

You’ve heard of Grand Canyon National Park, and it, too, would be worthy of this list. But Utah’s Bryce Canyon National Park is just as spectacular. Its massive amphitheater teems with thousands of red rock hoodoos unlike anywhere else on the continent. Once you’re here, you can skip the parking lots by exploring with a guide via e-bike, or you can hop on a guided hiking trek down into the canyon itself and picnic there—just make sure to leave no trace.

While many national parks tout their contrasts, Olympic National Park takes the cake with landscapes spanning rocky shorelines, ancient rainforests, and snow-capped mountaintops—a nearly 8,000-foot (2,438-meter) elevation change across the Olympic Peninsula. Well-known for spots like Rialto Beach and the Hoh Rainforest (one of the largest temperate rainforests in the US), there’s always somewhere in Olympic to go, year-round. What’s more, getting there is easy: day tours from Seattle abound.

The only national park in America’s northeast, Acadia National Park is an old Rockefeller haunt, where the country’s wealthiest families once escaped into nature. Here, discover national park history between the rocky shorelines, gentle mountains, and fjord-like waters. Visitors can spot historic lighthouses, nosh on traditional popovers and afternoon tea, and travel down old carriage roads. Hiking here, especially on a guided tour, is apt for beginners and family-friendly.

Unlike most parks—especially the big-ticket ones—Great Smoky Mountains National Park has zero national park entrance fees. That’s right: It’s free to visit this national park and traverse its hardwood forests, spot black bears in Cades Cove, climb up to the top of Clingmans Dome, and more. A self-guided driving tour is an easy way to explore this ancient, biodiverse wonder, but you could also opt for a waterfall hike or overnight backpacking adventure.