Biosphere tours ... In 1991, eight men and women locked themselves inside an enormous glass-and-steel shell in the mountains north of Tucson to see if they could survive for two years with no outside help. The $150 million lab—Biosphere 2—was a miniature replica of Earth (Biosphere 1) and resembled a vast greenhouse. It was sealed off from the elements but contained its own farm, savanna, rain forest, and tiny sea. Bankrolled by Texas oilman Edward P. Bass, Biosphere 2 was envisioned as the first step toward the human colonization of Mars: If people could live in an airtight bubble on Earth, perhaps they could live in a bubble on Mars. The experiment was not a smashing success. The Biospherians stuck it out for the two years, but oxygen levels fluctuated dangerously, crop production was less than robust, and all the animals except for ants and cockroaches reportedly died. While Mars remains unmarred by human footprints, last year Biosphere 2 opened its doors for more extensive public exploration. The one-hour guided "World of Discovery" Under the Glass tour is strange and fascinating. It begins in the futuristic white kitchen where the Biospherians prepared and ate their spartan meals of grains and beans. It's possible to wander from the kitchen to the nearby command center, which regulates the temperatures of the different ecosystems inside Biosphere. Visitors will note the temperature changes. The tour proceeds along a path through dry savanna, mangrove forests, thorn scrub, and a foggy coastal desert. It passes right by an "ocean," which consists of 750,000 gallons of salt water in a tank the size of an Olympic pool. A wave machine keeps the water moving gently and there is even a light breeze. The tour finishes inside the structure's "lung," in the middle of which hangs a 16-ton aluminum disk that was once used to control the lab's air pressure. Tours often encounter scientists, diving into the ocean or taking measurements. The lab has found new life: It is run by Columbia University and is used by researchers from around the world to study the effects of global warming. If you're going . . . The "World of Discovery" Under the Glass tour costs $10 per person, in addition to the Biosphere 2 admission price. For information, call (520) 838-6200 or visit www.bio2.edu.     by Matt Samelson

Despite Tucson's cultural richness, travelers seeking a Southwestern vacation tend to relegate it to also-ran status—behind Santa Fe for art, the Grand Canyon for scenery, and Phoenix for urban pampering. This is an unfair designation if ever there were one. The fact is, Tucson's terrain is some of the most staggeringly dramatic in the West, and its array of galleries, museums, and restaurants easily rivals that of trendier Santa Fe and far bigger Phoenix. "The independent restaurant scene is actually stronger here than in Phoenix," says Janos Wilder, a James Beard Award winner who owns two local eateries, Janos and J Bar. "Tucson is a melting pot, with ethnic restaurants here of every description. Yet they're less expensive than comparable places on the West Coast."

Tucson also has some of the most delightful weather in the nation—except in the summer, that is, when blistering temperatures make even lifelong residents bear hug their air conditioners. But from November through April, the city revels in cool days, chilly nights, and minimal rain. Making the most of this climatic nirvana, Tucson tends to crowd its win-ter and spring calendar with street fairs, parades, ethnic festivals, and a major rodeo.

So why does this gem of a city tend to get overlooked? Perhaps because Tucson makes you work harder to hit all the highlights. As the city spills ever northward into the desert, the restaurants, art galleries, nightclubs, and historic sights are widely scattered—not corralled in an easily identifiable tourist district.

One walkable exception is the area around the University of Arizona, a hotbed of bohemian coffee shops and stellar museums. In a single afternoon, I saw original Ansel Adams prints at the Center for Creative Photography, marveled at richly illustrated panels from a 15th-century Spanish altarpiece at the University of Arizona Museum of Art, and learned a bit about the history and spiritual beliefs of Southwestern Indians at the Arizona State Museum.

For all Tucson's sprawl, pristine stretches of wilderness still lie at its doorstep. Lush, floral, and full of life, the surrounding Sonoran Desert erased any assumptions I had about deserts being barren, Lawrence of Arabia-style sandpiles. "The Sonoran Desert is a feast for the eyes," says Diana Madaras, a Tucson artist. "In the daytime, you have bright clear light that creates these great shadows. And at sunset, there's a pink-purple cast to everything. It's a very dynamic desert."

It's also a layer cake of ecologies. On successive days, I trekked through groves of hat rack-shaped saguaro cacti at Saguaro National Park and a conifer forest on the crest of 9,157-foot Mount Lemmon, where temperatures are typically 30 degrees cooler than they are in Tucson. Mount Lemmon also boasts the southernmost downhill ski area in the continental United States.

At Sabino Canyon in the Coronado National Forest, I hopped a tram that follows a steep paved path for nearly four miles through that rarest of desert phenomena, a stream-fed oasis. The water draws plant and animal species that normally wouldn't be caught dead sharing the same address, including sycamores, saguaro cacti, Gila monsters, freshwater jellyfish, and tiny hummingbirds. The bird life around Tucson is extraordinarily diverse. "It's one of the nation's birding hot spots," says Sonja Macys, executive director of the Tucson Audubon Society.

Meanwhile, the urban options for working up a sweat are as varied as your footwear. After dark, country music fans can get in touch with their inner Billy Ray Cyrus at the Cactus Moon, a rollicking music club where line-dancing devotees ranging in age from 21 to eightysomething kick up their cowboy boots. Nearby, the restaurant El Parador backs up its Pan-Hispanic menu with weekend salsa bands and a dance floor that draws salsa aficionados from across the city. (Both clubs offer beginning dance lessons.) If you prefer watching other people sweat, that's no problem, either. Three major league baseball teams—the Chicago White Sox, the Arizona Diamondbacks, and the Colorado Rockies—come to town for spring training. Workouts begin in February and the games run throughout March.

Tucson also abounds with arts and crafts that celebrate the region. At the Medicine Man Gallery you'll find gorgeous Zuni turquoise rings for $65, $1,000 Navajo rugs that date back to the early 1900s, and $1 million paintings by the likes of Georgia O'Keeffe and Maynard Dixon. At Old Town Artisans, a square block's worth of shops housed inside a historic 1850s building whose ceilings still consist of exposed saguaro cactus ribs and barrel staves, I perused pretty much every type of decorative art produced in the Southwest. I found horsehair pottery from New Mexico, handcrafted Day of the Dead-style skeleton figurines, and cute $6 folk-arty cascarones—party favors consisting of confetti-filled eggshells. "All over the border country, cascarones are used at parties to break over the heads of other partygoers," says local folklorist James Griffith. "Here in Tucson, the tradition is to create these elaborately dressed figurines that have eggshell heads. They're a truly spectacular local art form."

The town is also overflowing with restaurants that offer a sophisticated twist on standard desert fare. At the posh Tack Room, situated in a former hacienda, I feasted on fabulous quail with chorizo-corn bread stuffing. At Janos, where chef Wilder combines elegant French techniques with traditional Southwestern fare, the menu includes guava-roasted duck, Anaheim chiles stuffed with lobster, and dark chocolate-jalapeño ice cream. If your tastes are a little more conventional, try Li'l Abner's Steakhouse—a former stagecoach stop—for the hefty two-pound steaks grilled over a mesquite fire. Dean Armstrong and the Arizona Dance Hands—the house band on Fridays and Saturdays—play vintage country-western tunes that could make Hank Williams weep into his Tecate.

In South Tucson, which is brimming with Mexican restaurants, the cooking style comes straight from the state of Sonora. The menus play up flour tortillas, beef, green-corn tamales, and horchatas (a creamy drink made of rice water, sugar, and cinnamon), all in huge portions at bargain prices.

Many of the popular Mexican eateries are as much happenings as they are restaurants. At El Guero Canelo, customers of all backgrounds congregate to wolf down giant beef-filled burros. At Mi Nidito, I tested my appetite against Bill Clinton's and came up short—unable to polish off the President's Plate, a tostada, taco, tamale, enchilada, and chile relleno combination platter named for the former president, who dined here while in office. It's worth the trip just to scan the VIP customer photos in the front lobby, easily the only one in which you'll ever see Julio Iglesias, William Shatner, and Madeleine Albright in the same place.

But it was at BK, a roadside stand, that I enjoyed what may be Tucson's greatest delicacy, the Sonoran hot dog: a bacon-wrapped wiener inside a bun, smothered with beans and a Mexican flag of salsa, mustard, and mayo. It may have cost me a coronary artery, but it was worth it. Besides, it's probably the only wild thing in the Sonoran Desert that doesn't bite back.