The Battle of the Bulls Monument on the San Pedro River near Sierra Vista, Arizona marks the only combat engagement of the Mormon Battalion during its remarkable 2,000-mile march from Iowa to San Diego in 1846 — a chaotic confrontation with a stampeding herd of wild bulls at The Narrows that left three men wounded, three mules gored, and at least nine bulls dead, commemorated by a stone marker erected by Boy Scout Troop 21 in 1960.

Boyce Thompson Arboretum near Superior, Arizona is the oldest and largest botanical garden in Arizona — a 392-acre living museum of over 12,000 arid-land plants from the deserts of the world, set along Queen Creek at the foot of Picket Post Mountain, with five miles of trails, the historic Clevenger House herb garden, world-class birding, and three nationally accredited plant collections.

City of Rocks State Park in southwestern New Mexico is one of the most geologically striking and unusual campgrounds in the American Southwest — a one-square-mile cluster of volcanic rock columns and pinnacles rising up to 40 feet from the Chihuahuan Desert floor, formed 34.9 million years ago from a massive volcanic eruption and shaped by millions of years of erosion into a landscape so otherworldly that camping among the formations feels like sleeping inside a sculpture.

Colossal Cave Mountain Park near Vail, Arizona offers cave tours, hiking and biking trails, horseback riding, camping, and picnicking across a 2,400-acre historic park featuring the crystal-filled Colossal Cave and the 120-year-old La Posta Quemada Ranch. Campsites are tucked among saguaro cacti and mesquite trees in Posta Quemada Canyon — 30 primitive sites across El Bosquecito and La Selvilla, both with water and restrooms. First-come first-served, $15/night. No electricity or RV hookups.

Cove Fort Historic Site near the junction of I-15 and I-70 in south central Utah is the only fort built by The Church of Jesus Christ of Latter-day Saints in the 1800s that still stands — a 100-foot square volcanic rock fort built in 1867 by Ira Hinckley at the direction of Brigham Young as a way station for travelers, the Pony Express, and the Deseret Telegraph between Salt Lake City and the Mormon settlements of southern Utah, Nevada, and California.

Dos Cabezas Pioneer Cemetery is a hillside frontier graveyard in the ghost town of Dos Cabezas near Willcox, Arizona — the final resting place of approximately 180 pioneers, miners, ranchers, and families from the 1870s onward, with many unmarked graves and a plaque honoring those whose names are known but locations are not.

Fort Verde State Historic Park in Camp Verde is the best-preserved example of an American Indian Wars period fort in Arizona — a 12-acre state park preserving the original 1870s administration building and three officers' row houses, all furnished in period style, with museum exhibits covering General Crook's campaigns, the Buffalo Soldiers, US Army Signal Corps, and the scouts and soldiers who served in the Verde Valley from 1865 to 1891.

Frijole Ranch Cultural Museum in Guadalupe Mountains National Park is the most complete example of early farming and ranching enterprise in the Guadalupe Mountains — a historic ranch complex built in 1876 beside natural springs at the foot of the Guadalupe escarpment, listed on the National Register of Historic Places, and preserved today as a museum tracing the human history of the Guadalupes from Native Americans through the pioneer ranching era to the establishment of the national park.

Jerome State Historic Park perches on Cleopatra Hill above the Verde Valley in Jerome, Arizona — home to the 1916 Douglas Mansion, Arizona's largest adobe structure and now a remarkable copper mining museum with period rooms, a 3D model of the underground mines, mineral exhibits, and sweeping panoramic views of the Verde Valley and Sycamore Canyon.

Kitt Peak National Observatory rises to 6,877 feet in the Quinlan Mountains of the Tohono O'odham Nation southwest of Tucson — home to the largest collection of major optical research telescopes on Earth, with daytime tours of historic telescope domes, sweeping Sonoran Desert views, and nighttime stargazing programs that have drawn over 2 million visitors since 1964.

Lincoln Historic Site in Lincoln, New Mexico is the most widely visited state historic site in the state — a half-mile stretch of one road that is the entire town, frozen at the moment of the Lincoln County War of 1876–1879, where Billy the Kid shot his way out of the Old Lincoln County Courthouse on April 28, 1881, killing two deputies whose death markers still stand where they fell, and where 17 original structures including the Tunstall Store, the Torreon Tower, and the Church of San Juan Bautista tell the story of five cultures competing for control of the largest county in the United States.

Lowell Observatory on Mars Hill in Flagstaff, Arizona is one of the most historically significant astronomical research institutions in the world — a National Historic Landmark where Pluto was discovered in 1930, where the first evidence of the expanding universe was detected in 1912, and where the 24-inch Clark Telescope built in 1896 still operates for public viewing beneath some of the darkest skies in the American Southwest.

Navajo Bridge at Marble Canyon, Arizona spans the Colorado River 467 feet above the water — one of only seven crossings of the river for 750 miles, with two steel arch bridges side by side, a free interpretive center, and some of the most dramatic canyon views in the Southwest accessible to anyone willing to walk out onto the 1929 historic pedestrian bridge.

Picacho Peak State Park along Arizona's I-10 corridor is one of the most historically layered state parks in the Southwest — a striking volcanic peak rising 1,500 feet from the Sonoran Desert floor, site of the westernmost battle of the American Civil War, a showcase for spring wildflower blooms that draw visitors from across the state, and a developed campground with 85 electric sites just 45 miles from both Phoenix and Tucson.

Robbers Roost Trail near Sedona leads to a historic outlaw hideout cave in the red rock country of the Coconino National Forest — a rocky trail through classic Arizona high desert to a cave with framed views of Sedona's red rock cliffs, a dozen or more deer grazing in the canyon below, and dispersed camping available along the adjacent FR 258 Buckboard Road for those looking to stay.

Sun Tunnels is one of the most significant works of Land Art in North America — four massive concrete tunnels arranged in an X configuration in the Great Basin Desert near Lucin, Utah, aligned with the rising and setting sun of the summer and winter solstices, pierced with holes that cast constellation patterns of light across the dark interiors, and built on forty acres of desert purchased by artist Nancy Holt specifically as the site for the work in 1973 to 1976.

The Titan II Missile Interpretive Site inside the Ironwood Forest National Monument near Marana, Arizona is one of 18 former nuclear missile launch sites that once ringed Tucson during the Cold War — a decommissioned silo where a 9-megaton warhead sat on 58-second launch readiness for over 20 years, now open to the public as a free interpretive site.

Topaz Internment Camp near Delta, Utah is the site of one of the largest WWII Japanese American internment camps — where nearly 8,000 American citizens were confined from 1942 to 1945. A small museum in Delta preserves their story.

Two Guns is one of Arizona's most haunted and storied Route 66 ghost towns — a cursed stretch of Canyon Diablo where a Navajo massacre, a Wild West showman, a mountain lion zoo, a murder, and a devastating fire all converged on the same dusty patch of high desert east of Flagstaff.

West Fork Oak Creek Trail in Oak Creek Canyon is consistently ranked among the finest hikes in Arizona — a 6.6-mile round trip through a narrowing red rock canyon alongside the West Fork of Oak Creek, past the ruins of the historic Mayhew Lodge, beneath towering cliffs hundreds of feet tall, with thirteen creek crossings and a canyon that gets more dramatic the further you go.

Yuma Territorial Prison State Historic Park preserves Arizona's first prison — a bluff-top fortress on the Colorado River where over 3,000 inmates were confined between 1876 and 1909, including stagecoach robber Pearl Hart. Walk through original strap iron cells, explore the dark cell, and learn the colorful and often brutal history of the Wild West's most notorious lockup.