Zipping along Interstate 5, you once could bypass Redding, Calif., like a barely noticed speed bump between Sacramento and the Oregon border. Now there's a reason to stop.

The city's new Sundial Bridge, a soaring glass, steel and granite pedestrian span by Santiago Calatrava that opened July 4, entices you to pull over. The bridge features a 217-foot-tall pylon "sundial" -- in the famed Spanish architect's signature color of bold white -- that slants high above the Sacramento River's tree-dense banks. The inquisitive can stroll along the 700-foot-long, 23-foot-wide bridge, which is suspended by a row of gracefully angled cables.

Redding civic leaders hope the bridge brings people to the river and to the center of this burg of 85,000, the largest California city north of Sacramento.

"This is a community gathering area that provides Redding with a sense of place," said John Mancasola, executive vice president of the McConnell Foundation, a Redding philanthropic organization that funded most of the project.

An artist, engineer and architect, Calatrava is renowned for his bridges, airports and rail terminals. His virtuosity is apparent whether you see the asymmetrical Sundial Bridge from a distance or observe the details closely while crossing it.

But a real surprise comes on the north side of the span -- where it becomes evident that the giant sundial actually marks off the midday hours on plaques set into the semicircular upper plaza. From that point, visitors spiral down to the river-level plaza, which feels as if you're walking into the center of a giant curved sculpture. A rounded overhead opening in the immense white structure reveals blue sky and a spectacular view of the pylon's tall tapering spindle.

Light slips through oblong slots cut into the sundial's hollow triangular core, creating patterns that interplay and shift with the sun's movement. Geese paddle in the water, and finches, sparrows and hummingbirds swoop singing through the adjacent McConnell Arboretum.

If you're exploring the area, the bridge marks the entrance to the Sacramento River Trail, which winds for 10 miles along the river. The span also links the north and south sections of the 300-acre Turtle Bay Exploration Park, which comprises the arboretum, a nature museum and the visitors center, an amphitheater, a kids' play area and a summer butterfly house. Botanical gardens will open next year.

The 220-acre arboretum takes up a big chunk of the park's north side and nurtures some of the last remaining riparian forest on the river, said Turtle Bay spokeswoman Virginia Germann as we strolled across the translucent span. "Salmon spawn here," she said, explaining why no bridge supports were sunk into the river's endangered species breeding ground. Indeed, without thick moorings, the bridge seems to float airily above the water.

Once dependent on its now-defunct lumber industry, Redding is in a turnaround mode. Other recent additions include an aquatic park that opened last year, an almost-complete sports complex and a spacious new City Hall. A 129-acre parcel of land near the Redding airport will become a park with walking trails and playing fields.

Another architectural gem, downtown's landmark Cascade Theatre (1935), reopens Aug. 14. A painstaking restoration process uncovered several beautiful art deco nudes beneath the layers of pea-green ceiling paint that had hidden them for decades.

Outside of town is Shasta Lake and its mammoth dam, forests and hundreds of fish-filled streams. Mount Shasta, a 14,162-foot dormant volcano with skiing in the winter and climbing in summer, towers in the distance. If drifting on a houseboat appeals to you, Shasta Lake marinas provide rentals. For those who like to learn their history on the prowl, the remnants of a gold rush-era town are a short drive west at the Shasta State Historic Park.

But that's a page out of the past. In Redding, the Sundial Bridge is pointing toward a new beginning. And it's about time.

-- Christine Vovakes

For more information on Redding and the Sundial Bridge: Redding Convention and Visitors Bureau, 800-874-7562, www.visitredding.org. Admission to Turtle Bay Exploration Park (840 Auditorium Dr., 800-887-8532, www.turtlebay.org) is $11 and includes all attractions. The bridge is free and open from dawn to dusk.

The Sundial Bridge in Redding, Calif., tells time and links a 300-acre park.