Yellowstone National Park is a life-list destination for millions of people—not just Americans—the world over. That’s because you won’t find a place like this anywhere else on the planet: No other region combines rare geothermal fireworks, skyscraping mountains, glaciers, and a huge variety of wildlife such as grizzly bears, wolves, elk, and moose in one spot the way the Greater Yellowstone Ecosystem does. Here, you can spend days getting lost among the geysers and hot springs, gazing up at or down from towering peaks, marveling at incredible waterfalls, sniffing carpets of wildflowers, and scoping for that next thrilling wildlife sighting. There’s something for everyone at these two exceptional parks—and as soon as you check this place off your life list, you’re bound to start dreaming about your next visit. 

Creatures great and small thrive in Yellowstone National Park. In the wilderness of Yellowstone’s southern corners, grizzlies feed on cutthroat trout during their annual spawning run to the Yellowstone headwaters. In the soft blue depths of Octopus Pond, microbes of enormous scientific value are incubated and born; in the mountain ridges, gray wolves make their dens and mountain lions hunt bighorn sheep.

When John Colter, a scout for Lewis and Clark, first wandered this way in 1807, his descriptions of geysers, sulfurous hot pools, and towering waterfalls drew jeers and suspicion. No one doubts him now, but these are still places you should see for yourself. The explorers of today come in minivans and on bicycles, aboard snowmobiles and telemark skis, and in such numbers that the parks sometimes seem to groan under the strain.

In the early days of Yellowstone, first established as a national park in 1872, visitors were so sparse that their unregulated activities—catching 100 trout at a time, washing their underwear in the hot pools—left few noticeable scars. Now, with millions of people visiting the park annually, the strain on everything from sewer systems to fish populations is immense. Yet while there are problems, these parks still radiate extraordinary beauty: the jagged Tetons, the glassy surface of Jenny Lake, the awe-inspiring Grand Canyon of the Yellowstone, the towering Obsidian Cliff, the steamy meandering of the Firehole River. Wildlife that most Americans see only in zoos wanders freely here, from the grizzly to the river otter, the trumpeter swan to the rufous hummingbird. Aspen groves, fields of lupines, the howls of coyotes and wolves—all testify to the resilience and vitality of the Greater Yellowstone Ecosystem, which extends outside the borders of the park.

This is not just a paradise for sightseers—it’s a scientific preserve as well. The hot pools support a population of unique microbes known as thermophiles and extremophiles; studies of the elk herds and grizzlies have yielded crucial information on habitat needs and animal behavior; and the rocks of Yellowstone present the Earth turned inside out—a treasure trove for geologists.

Most visitors will see or know little of this; they park in a pullout on U.S. 191/89/26 to watch Old Faithful erupt. If you have more time, however, I suggest that you take little sections of this park—just, say, Yellowstone’s northeast corner, the Lamar Valley—and savor them in all their fine detail, rather than embark on a madcap race to see every highlight.

Above all, definitely get out of your car and away from the road, into the wild heart of the backcountry. This park embodies our country’s beginnings: as a landscape of wilderness, of challenging and rugged extremes, and of extraordinary bounty and beauty. Use this guide as a set of footprints to help you find your way there.

Grand Loop Road, the 154-mile, figure-eight road looping through the heart of the park, connects most of the major and minor attractions, and you’re bound to spend some time cruising it. But stop frequently and get out of the car: Exploring the park’s highlights and, even better, getting out into the backcountry on a hiking trail will enrich your trip by leaps and bounds. 

You could visit Yellowstone for a single day—and if that’s your only option, by all means, take it—but you need a minimum of 3 days to really get a feel for the place. A week or more is even better. Hit up the must-sees, such as Old Faithful, Grand Canyon of the Yellowstone, Mammoth terraces, Lamar Valley, and Yellowstone Lake, but also to check out some of the lesser-known but still incredible destinations. Attend a ranger-led program or sign up for a class with Yellowstone Forever for an in-depth experience. Consider spending a night under the stars, either in a drive-in park campground or deep in the backcountry. The farther you go from the road, the more solitude you’ll enjoy, and the more Yellowstone’s wild heart will be revealed to you.

Yellowstone closes in fall and then reopens as a winter destination come December, when cross-country skiing, snowshoeing, and snowmobiling are the prime pursuits. There's no cozier place than the lobby of the Old Faithful Snow Lodge, the only hotel in the park's interior that stays open during Yellowstone's long, cold, and snowy winter season. I highly recommend a visit when snow covers the ground. You often have the park to yourself, but dress appropriately (read: no less than three layers) and be ready to incur an extra expense in the form of snowcoach fare.

Watch Your Step! -- In thermal areas, the ground might be only a thin crust above boiling hot springs, and there's no way to guess where a safe path is. New hazards can bubble up overnight, and pools are acidic enough to burn through boots; so stay in designated walking areas.

Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.