REDDING, Calif. — Seen through the green glass deck of Sundial Bridge at Turtle Bay, the Sacramento River is a sun-dappled abstract watercolor. It is a beautiful thing, this bridge for pedestrians, a sculpture in steel, glass and granite. At night, when the free-standing bridge is illuminated from underneath, it glows.

REDDING, Calif. — Seen through the green glass deck of Sundial Bridge at Turtle Bay, the Sacramento River is a sun-dappled abstract watercolor. It is a beautiful thing, this bridge for pedestrians, a sculpture in steel, glass and granite. At night, when the free-standing bridge is illuminated from underneath, it glows.

Perhaps the $23.5 million bridge, designed by famed Spanish architect-engineer Santiago Calatrava, hasn't completely transformed Redding — a town of 90,000 150 miles north of Sacramento on Interstate Highway 5 — but it surely has given it a new image. The bridge is now Redding's No. 1 tourist attraction.

"It has made Redding a destination," Mayor Dick Dickerson says.

With the bridge, Redding has become more than a base camp for exploring nearby Mount Shasta and Shasta Lake, Lassen Volcanic National Park and Shasta Dam.

"We had turned our back to the river," says John A. Mancasola, a lawyer who grew up in Redding and played a major role in luring Calatrava to design the bridge. Now the landmark has opened a window on the waterway.

"It's just wonderful to watch how people of all ages visit the bridge — families with kids in strollers, a grandmother in a wheelchair," says Pam Gluck, executive director of Redding-based American Trails, a national trails organization.

And, she says, having the bridge as a new gateway to the Sacramento River National Recreation Trail has attracted more joggers, cyclists and hikers.

There are other bridges across the Sacramento — albeit not bridges that look like this one, which resembles an egret in flight — but a bridge at this site was essential to link the two campuses of 300-acre Turtle Bay Exploration Park. On the north bank is the vast McConnell Arboretum, and on the south bank an interactive museum-aquarium focusing on regional history and ecology, a kid-friendly forest camp and a river-view cafe.

In the three years since it opened, Sundial Bridge has become, in essence, the town square. The naysayers who wanted a wooden bridge recalling Redding's history as a lumber city, and the grumblers who thought Redding had contracted a bad case of "big city-itis," are largely silent.

So why would such a celebrated architect design his first free-standing U.S. bridge for little Redding?

Because someone asked him to — specifically Mancasola, vice president and in-house counsel of the McConnell Foundation, which underwrites many community projects.

The foundation, with a $400 million endowment, agreed to help fund a new bridge. After a search for a designer, the city and community selected a modest $2.8 million single tower suspension span, but hit an impasse over choosing a builder. Because no one loved the design, Mancasola suggested Calatrava.

In April 1995, Calatrava made the first of six visits to Redding, walking the riverbanks and flying over in a helicopter. The mountains reminded him of Valencia, near his hometown in Spain. The bridge also presented a challenge: It was not to touch the river, which is a protected spawning bed for chinook salmon.

Groundbreaking was in 1999. As work progressed, costs rose. Calatrava abhorred bare concrete and insisted that surfaces be covered in broken white Spanish tiles, 1.3 million pieces. The bridge's intricate engineering required pipes from Spain, cables from England, glass decking from Canada, and stone for the bridge plaza from Italy and Mexico. The towering pylon was brought in segments by barge and truck from Vancouver, Wash.

In the end, the McConnell Foundation contributed $13 million, the city ponied up $2 million, and $8 million came from state and federal grants.

The initial bounce in tourism — 121,000 additional hotel nights with $1.7 million in added tourist dollars in the first four months after the bridge opened — was not a one-time blip.

"People are coming from all over — Japan, the U.K., Belgium, Germany, Spain," says Bob Warren, tourism-bureau manager. "Calatrava has a pretty strong following."

The eight-mile loop of the Sacramento River Trail on both sides of the river is a paved path partly shaded by cottonwood and oak trees. The river, a clear blue green, is framed by dramatic rock formations, including views of snow-frosted Mount Lassen. When construction is completed, the trail will extend to Shasta Dam.

But the bridge hasn't revamped Redding's neglected downtown and its history of gold-seeking Forty-Niners. Downtown fell on hard times in the early 1970s.

"Redding was starting to look like a suburb without a downtown," says John Truitt, director of the nonprofit Viva Downtown Redding, which is revamping the city's core.

Viva Downtown's Marketfest, a Thursday-evening farmers market with live music and crafts in Library Park, now draws crowds.

Although a 1885 fire razed many old wooden buildings, visitors can get a guide to the remaining historic structures at Viva Downtown's office, next to the restored 1934 Art Deco Cascade Theater.

Boutiques have opened downtown, and the new Cascade Square will be a retail hub. Riverfront Playhouse plans to relocate from an industrial strip mall across town next year. Market Street Steakhouse, not quite a year old, draws crowds downtown.

"Local people want the downtown revitalized," says Dickerson. "We'll bring them back."

For many tourists, Redding equals "hotter than heck and fast food," says Stephen Gaines, Best Western Hilltop Inn owner and Redding Hotel-Motel Association board member.

Gaines opposed the bridge, buying into the untrue argument that the bridge would be built with taxpayer dollars needed for things such as filling potholes. He now lauds Sundial Bridge.

"It bolstered the economy in many, many ways," Gaines says. "We're a spot on the map now."