Walking beneath Tonto Natural Bridge in central Arizona feels like walking through a portal to another world. The bridge is believed to be the largest “travertine” bridge of its kind, meaning it’s made from limestone deposited around mineral springs. There are pools at its feet, and a verdant coat of greenery above it, making for a striking vista. The bridge was authorized as a state park in the late 1960s, and is reachable by trail. There’s a more accessible paved trail that accommodates all sorts of hikers, and a rougher unpaved trail that follows the nearby riverbed. On a hill above the bridge also sits the historic Goodfellow Lodge, which is beautiful to look at but not currently open for reservations.

While Arizona is known for its many above-ground wonders, it also offers special underground marvels, too. This massive cave in the Coconino National Forest near Flagstaff is staggering; at its highest point, the cave walls reach 30 feet, and it’s all thanks to lava. Unlike other caves, where you’ll find stalagmites and stalactites hanging above and below you, this cave has smooth walls: it was formed from a giant lava flow whose exterior hardened but whose interior stayed molten, creating an underground tube. While other lava tube caves exist in the world, this one is notable for a Y-shaped intersection deep inside, which implies two tubes of lava flowing into one. If you’ve ever dreamed of spelunking, don’t miss it.

Between 700 and 1300 B.C. what is now Flagstaff, AZ was inhabited by the Sinagua people, whose petroglyphs still decorate this canyon that lies inside the city’s borders. These petroglyphs depict geometric shapes and scenes of tribal life, including archers, and local animals like deer, elk, bighorn sheep, and water birds.

For a long time, as the city of Flagstaff expanded, few people knew about these petroglyphs. The area was damaged in the 20th century by looters, trash heaps, and a gas line. Eventually, local residents advocated for a cleanup of the area, and the canyon preserve was added to the National Register of Historic Places in 2008.

Today, the preserve includes three trails of varying lengths as well as a waterfall accessible from the Tom Moody trail. The petroglyphs are visible throughout the park, a striking bit of art history within the city of Flagstaff.

This trail shows you some of the greatest, most dramatic rock formations in the state of Arizona. The stars of the show are “hoodoos,” or pinnacles of the Chiricahua National Monument, formations that the Apaches called “standing up rocks”. These tall rock spires are formed by erosion, when a soft rock like mudstone is covered by a thin layer of hard rock like limestone; cracks in the outer layer allow the interior soft rock to erode. These hoodoos are made from small caps of harder rock, which protect what’s left of the interior layer from erosion. 

There are a few particularly famous rock formations among these hoodoos: Totem Pole Rock is impressively tall and even, like its namesake; Big Balanced Rock connects to its supportive base by an improbably narrow neck, like an hourglass; Mushroom Rock has a tiny base and an enormous head, and looks like something dropped down to earth. Among the rocks are also a wide range of plants, like prickly pear cactus. These sights make for one of the most scenic and undersung hiking routes in the state.

Just 14 miles north of the US-Mexico border, Arch Canyon Trail lies within Organ Pipe Cactus National Monument. The monument, which is also a UNESCO biosphere, was designated to protect its namesake cactus, and is the only place in the country where the senita and organ pipe cacti grow wild. While hundreds of miles of trails wind through the park, Arch Canyon Trail offers some of the most spectacular vistas.

The trail is deceptively strenuous: while the official trail is an easy 1.2 miles, adventurous climbers have designated a scramble of a trail up 2.4 more miles of hiking-slash-climbing that ends at a pair of natural arches and breathtaking views of the park; you can easily see into Mexico, and far across the state, from that vantage point. Just be very careful when you’re climbing.

From above, Glen Canyon looks like a picturesque, pre-programmed laptop screensaver. The green-tinged, man-made Lake Powell weaves through what was once a canyon. In the late 1960s, the United States Bureau of Reclamation built a dam on the Colorado river to create the lake, and filled the canyon to the dismay of many environmentalists. Edward Abbey, the crotchety poet laureate of the American West, likened the canyon’s beauty to that of the Taj Mahal after rafting through it in the pre-dam days.

Now, thanks to climate change, drought and decreasing water levels, Glen Canyon and its wind-smoothed walls are becoming more visible. Certain areas once reachable by boat are now reachable by hike. The Glen Canyon National Recreation Area is enormous: it spans over 1.25 million acres. All of this makes it an excellent place for leisure tourists in boats and intrepid hikers alike.

If you’re already in Glen Canyon, you can’t miss Cathedral in the Desert. This natural wonder has been exposed in recent years, given decreasing water levels; now it’s possible to hike in to see this awe-inspiring monument. In wetter years, this natural “amphitheater” lies 100 feet below the surface of Lake Powell. When the water drops low enough, you can see the canyon formation that mimics a cathedral: the sandstone canyon walls feature projections that resemble a church’s spires. At one end, a 60-foot waterfall pours into the canyon. Whether or not you’re interested in “holy” places, this is one you won’t forget. 

This is another geological wonder that seems to have been plucked from a screen saver, or land art catalog, or big-budget science fiction film. White Pocket forms part of the Paria Plateau in the Vermillion Cliffs National Monument; it constitutes a collection of white-capped domes and ridges beneath a large mesa. It’s called a “pocket” because it’s a small bit of land that’s notably different from its surroundings—here, those surroundings are unassuming plains, sandy and spotted with bushes. Among them appears the pocket, with its variegated, swooping patterns that at times look like a wide, flat waterslide sloping towards a nearby pond. Accessing White Pocket can be tricky: a four-wheeler is mandatory, so your best bet is to hire a local guide.