The dry, barren landscape of the Chihuahuan desert disappears into a subterranean cavern that is home to some of the most magnificent geological formations. Carved by now-evaporated waters of an inland sea several millennia ago, the Guadalupe Mountain holds as many as 119 clandestine caves. Craggy formations, each fascinating in its distinct form, stay suspended from the cave's roofs, the karst-like remnants of limestone that was dissolved by sulfuric acid over great many years. A geological repository of sorts, the Carlsbad Caverns Park is home to a plethora of patterns, from The Big Room, a 4000 feet (1,220 meter) long chamber, to the Bat Cave, a guano-laced corridor that houses a majority of the caverns' bat population. The Lechuguilla Cave is perhaps the most fascinating, fabled for intricately contoured stalactites that cling to the roof, in what is deemed to be the second-deepest limestone cave in the United States.

Not far from Los Angeles, San Diego or Las Vegas, Joshua Tree National Park is a magnificent confluence of the Colorado and Mojave desert ecosystems. The park is framed by wind-blown desert terrains, enigmatic rock formations and gorgeous wilderness which enlivens its arid landscape. This desert park is home to numerous varieties of plants and animals that brave the climatic extremes and unpredictable rain. Even the park's namesake, the Joshua tree, resides here and blooms in the spring. With almost 800,000 acres (3,23,748.5 hectares) of land and three ecosystems surviving within it, the park offers glimpses of either a California Mountain Lion stalking its prey or a California Desert Bat flying overhead. Strewn across the park's seemingly-desolate expanse is a troupe of campsites, whereas its marvelous, inky black skies have been a subject of many astronomical observations. It also plays host to an array of activities like hiking, birding, and climbing.

The centerpiece of Mount Rainier National Park is the eponymous stratovolcano which is the highest peak in the Cascade Mountain Range in Washington, standing at a dizzying elevation of 14,411 feet (4,392 meters). The mountain dominates its primordial wildernesses with poise and grace, and its stratovolcano base is bound with a seemingly endless system of hiking and trekking trails. The area was originally inhabited by quite a few different Pacific Northwest tribes of Native Americans, with George Vancouver being the first European to see the mountain in 1792. Dotted with meadows and varied species of flora including vibrant wildflowers, the park facilitates activities such as cycling and climbing and also offers opportunities for camping.

A sea of pillars in shades of ochre and red stretch as far as the eye can see in Bryce Canyon. Called hoodoos, these pillars are shaped by eons of wind and water erosion into intriguing shapes that defy logic. The most spectacular formations are located in the Bryce Amphitheater; its castles, steep pink cliffs and towering pillars an expression of nature's stark beauty. At dawn and sunset the amphitheater is awash in a prism of warm hues. Inspiration Point, Sunrise Point and Bryce Point are a photographer's delight, promising breathtaking vistas that soothe the spirit and fire the imagination.

This UNESCO World Heritage Site is the United States' most-visited national park. Sprawled across a luxuriant expanse of 522,419 acres (211,416 hectares), the Great Smoky Mountains National Park is split down the middle by the State Line that demarcates the territories of North Carolina and Tennessee. The park is renowned the world over for its remarkably diverse flora and fauna, sheltered by a series of ridges drenched in the cool spray of cascading waterfalls. Dressed in a blanket of dense forests and wildflower-laden meadows stitched together by babbling streams and gushing rivers, spellbinding vistas lay around every corner amid the ancient Appalachian mountains. The scenery transitions with the seasons from the vivid green of summer and the riotous colors of spring to the warm cast of fall and the white shroud of winter. Amid this vibrant and varied landscape, close to 80 historic buildings preserve the southern Appalachian mountain culture, of which the pioneer homestead at Cades Cove is just one. With ample opportunity for activities like hiking, biking, fishing and more, the ethereal allure of the Great Smoky Mountains is impossible to ignore.

Worn by the elements over millennia, the picturesque landscape of the Zion National Park is a masterpiece in shades of vermilion and cream; the rugged cliffs offset by the lush green of the valley, its depths carved by the Virgin River and sheltered by the magnanimous arch of the vivid blue sky. Frothy waterfalls tumble down the sheer drop like delicate tinsels of lace, while the weeping rocks feed hanging gardens of moss. The park's emerald pools are visions from a mystical world of wonder, their distinctive color a vibrant contrast to the warm hues of the undulating rocks. From the varied wildlife to the grottoes and monolithic towers of sandstone, Zion National Park is not only Utah's oldest but also its most popular nature reserve. Traversed by numerous trails of varying ardor, the park is a paradise for hiking enthusiasts and outdoors adventurers of every stripe.

Death Valley National Park is famed for its extreme arid temperatures. While it's difficult to believe, much can survive the sweltering temperatures, which go up to 120 degrees Fahrenheit (49 degrees Centigrade), the park's desert wildlife proves otherwise. Home to the Bighorn Sheep, Coyote and the evergreen creosote bush, the desert changes through the seasons and offers up a burst of colors in spring when the wildflowers bloom spectacularly. Top scenic spots include Zabriskie Point, overlooking the multi-hued Furnace Creek, otherworldly Twenty Mule Team Canyon and the badlands, and the desolate Mesquite Flat Sand Dunes.